<SEC-DOCUMENT>0001193125-25-290638.txt : 20251121
<SEC-HEADER>0001193125-25-290638.hdr.sgml : 20251121
<ACCEPTANCE-DATETIME>20251121080329
ACCESSION NUMBER:		0001193125-25-290638
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		13
CONFORMED PERIOD OF REPORT:	20251121
ITEM INFORMATION:		Completion of Acquisition or Disposition of Assets
ITEM INFORMATION:		Other Events
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20251121
DATE AS OF CHANGE:		20251121

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			XOMA Royalty Corp
		CENTRAL INDEX KEY:			0000791908
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				522154066
		STATE OF INCORPORATION:			NV
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39801
		FILM NUMBER:		251504650

	BUSINESS ADDRESS:	
		STREET 1:		2200 POWELL STREET
		STREET 2:		SUITE 310
		CITY:			EMERYVILLE
		STATE:			CA
		ZIP:			94608
		BUSINESS PHONE:		510-204-7239

	MAIL ADDRESS:	
		STREET 1:		2200 POWELL STREET
		STREET 2:		SUITE 310
		CITY:			EMERYVILLE
		STATE:			CA
		ZIP:			94608

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	XOMA Corp
		DATE OF NAME CHANGE:	20120119

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	XOMA LTD /DE/
		DATE OF NAME CHANGE:	19990107

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	XOMA CORP /DE/
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>d65279d8k.htm
<DESCRIPTION>8-K
<TEXT>
<XBRL>
<?xml version='1.0' encoding='ASCII'?>
<html xmlns:dei="http://xbrl.sec.gov/dei/2025" xmlns:us-types="http://fasb.org/us-types/2025" xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xoma="http://www.xoma.com/20251121" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:utr="http://www.xbrl.org/2009/utr" xmlns:iso4217="http://www.xbrl.org/2003/iso4217" xmlns:ix="http://www.xbrl.org/2013/inlineXBRL" xmlns:ixt="http://www.xbrl.org/inlineXBRL/transformation/2015-02-26" xmlns:ixt-sec="http://www.sec.gov/inlineXBRL/transformation/2015-08-31" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xbrldi="http://xbrl.org/2006/xbrldi" xmlns:us-gaap="http://fasb.org/us-gaap/2025" xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>8-K</title>
<meta http-equiv="Content-Type" content="text/html"/>
</head>
   <body><div style="display:none"> <ix:header> <ix:hidden> <ix:nonNumeric id="Hidden_dei_EntityRegistrantName" name="dei:EntityRegistrantName" contextRef="duration_2025-11-21_to_2025-11-21">XOMA Royalty Corp</ix:nonNumeric> <ix:nonNumeric name="dei:AmendmentFlag" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-322">false</ix:nonNumeric> <ix:nonNumeric id="Hidden_dei_EntityCentralIndexKey" name="dei:EntityCentralIndexKey" contextRef="duration_2025-11-21_to_2025-11-21">0000791908</ix:nonNumeric> </ix:hidden> <ix:references> <link:schemaRef xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xlink:type="simple" xlink:href="xoma-20251121.xsd" xlink:arcrole="http://www.xbrl.org/2003/linkbase"/> </ix:references> <ix:resources> <xbrli:context id="duration_2025-11-21_to_2025-11-21"> <xbrli:entity> <xbrli:identifier scheme="http://www.sec.gov/CIK">0000791908</xbrli:identifier> </xbrli:entity> <xbrli:period> <xbrli:startDate>2025-11-21</xbrli:startDate> <xbrli:endDate>2025-11-21</xbrli:endDate> </xbrli:period> </xbrli:context> <xbrli:context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember"> <xbrli:entity> <xbrli:identifier scheme="http://www.sec.gov/CIK">0000791908</xbrli:identifier> <xbrli:segment> <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">us-gaap:CommonStockMember</xbrldi:explicitMember> </xbrli:segment> </xbrli:entity> <xbrli:period> <xbrli:startDate>2025-11-21</xbrli:startDate> <xbrli:endDate>2025-11-21</xbrli:endDate> </xbrli:period> </xbrli:context> <xbrli:context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember"> <xbrli:entity> <xbrli:identifier scheme="http://www.sec.gov/CIK">0000791908</xbrli:identifier> <xbrli:segment> <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">xoma:M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember</xbrldi:explicitMember> </xbrli:segment> </xbrli:entity> <xbrli:period> <xbrli:startDate>2025-11-21</xbrli:startDate> <xbrli:endDate>2025-11-21</xbrli:endDate> </xbrli:period> </xbrli:context> <xbrli:context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember"> <xbrli:entity> <xbrli:identifier scheme="http://www.sec.gov/CIK">0000791908</xbrli:identifier> <xbrli:segment> <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">xoma:DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember</xbrldi:explicitMember> </xbrli:segment> </xbrli:entity> <xbrli:period> <xbrli:startDate>2025-11-21</xbrli:startDate> <xbrli:endDate>2025-11-21</xbrli:endDate> </xbrli:period> </xbrli:context> </ix:resources> </ix:header> </div> <div style="text-align:center"> <div style="width:8.5in;text-align:left;margin-left: auto;margin-right: auto"> <div style="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&#160;</div> <div style="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&#160;</div> <p style="margin-top:8pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman;font-weight:bold;text-align:center">UNITED STATES</p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman;font-weight:bold;text-align:center">SECURITIES AND EXCHANGE COMMISSION</p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman;font-weight:bold;text-align:center">Washington, D.C. 20549</p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="text-align:center"> <div style="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%;text-align:center;margin-left: auto;margin-right: auto">&#160;</div></div> <p style="margin-top:12pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman;font-weight:bold;text-align:center">FORM <span style="white-space:nowrap"><ix:nonNumeric name="dei:DocumentType" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-357">8-K</ix:nonNumeric></span></p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="text-align:center"> <div style="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%;text-align:center;margin-left: auto;margin-right: auto">&#160;</div></div> <p style="margin-top:12pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman;font-weight:bold;text-align:center">CURRENT REPORT</p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman;font-weight:bold;text-align:center">Pursuant to Section&#160;13 or 15(d)</p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman;font-weight:bold;text-align:center">of the Securities Exchange Act of 1934</p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:12pt; font-family:Times New Roman;font-weight:bold;text-align:center">Date of Report (Date of Earliest Event Reported): <ix:nonNumeric name="dei:DocumentPeriodEndDate" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt:datemonthdayyearen" id="ixv-358">November&#160;21, 2025</ix:nonNumeric></p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="text-align:center"> <div style="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%;text-align:center;margin-left: auto;margin-right: auto">&#160;</div></div> <p style="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman;font-weight:bold;text-align:center"> <span style=" -sec-ix-hidden:Hidden_dei_EntityRegistrantName">XOMA ROYALTY CORPORATION</span> </p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:center">(Exact Name of Registrant as Specified in Charter)</p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="text-align:center"> <div style="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%;text-align:center;margin-left: auto;margin-right: auto">&#160;</div></div> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table cellspacing="0" cellpadding="0" style="border-collapse:collapse; font-family:Times New Roman; font-size:8pt;width:100%;border-spacing:0;margin:0 auto">
<tr>
<td style="width:34%"/>
<td style="vertical-align:bottom"/>
<td style="width:32%"/>
<td style="vertical-align:bottom;width:1%"/>
<td style="width:32%"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;text-align:center"><span style="font-weight:bold"><ix:nonNumeric name="dei:EntityIncorporationStateCountryCode" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:stateprovnameen" id="ixv-359">Nevada</ix:nonNumeric></span></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><span style="font-weight:bold"><span style="white-space:nowrap"><ix:nonNumeric name="dei:EntityFileNumber" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-360">001-39801</ix:nonNumeric></span></span></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><span style="font-weight:bold"><span style="white-space:nowrap"><ix:nonNumeric name="dei:EntityTaxIdentificationNumber" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-361">52-2154066</ix:nonNumeric></span></span></td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<td style="vertical-align:top;text-align:center"> <p style="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">(State or Other Jurisdiction</p> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">of Incorporation)</p></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"> <p style="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">(Commission</p> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">File Number)</p></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><span style="font-weight:bold">(I.R.S. Employer<br/>Identification Number)</span></td></tr></table> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:center"><ix:nonNumeric name="dei:EntityAddressAddressLine1" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-362">2200 Powell Street</ix:nonNumeric>, <ix:nonNumeric name="dei:EntityAddressAddressLine2" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-363">Suite 310</ix:nonNumeric></p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:center"><ix:nonNumeric name="dei:EntityAddressCityOrTown" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-364">Emeryville</ix:nonNumeric>, <ix:nonNumeric name="dei:EntityAddressStateOrProvince" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:stateprovnameen" id="ixv-365">California</ix:nonNumeric> <ix:nonNumeric name="dei:EntityAddressPostalZipCode" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-366">94608</ix:nonNumeric></p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">(Address of Principal Executive Offices)</p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:center"><ix:nonNumeric name="dei:CityAreaCode" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-367">(510)</ix:nonNumeric> <span style="white-space:nowrap"><ix:nonNumeric name="dei:LocalPhoneNumber" contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-368">204-7200</ix:nonNumeric></span></p> <p style="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">(Registrant&#8217;s telephone number, including area code)</p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">(Former name or former address, if changed since last report)</p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="text-align:center"> <div style="line-height:6.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000;width:21%;text-align:center;margin-left: auto;margin-right: auto">&#160;</div></div> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Check the appropriate box below if the Form <span style="white-space:nowrap">8-K</span> filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:</p> <p style="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="border-collapse:collapse; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:4%;vertical-align:top;text-align:left"><ix:nonNumeric name="dei:WrittenCommunications" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:boolballotbox" id="ixv-369">&#9744;</ix:nonNumeric></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;text-align:left">Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)</p></td></tr></table> <p style="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="border-collapse:collapse; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:4%;vertical-align:top;text-align:left"><ix:nonNumeric name="dei:SolicitingMaterial" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:boolballotbox" id="ixv-370">&#9744;</ix:nonNumeric></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;text-align:left">Soliciting material pursuant to Rule <span style="white-space:nowrap">14a-12</span> under the Exchange Act (17 CFR <span style="white-space:nowrap">240.14a-12)</span></p></td></tr></table> <p style="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="border-collapse:collapse; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:4%;vertical-align:top;text-align:left"><ix:nonNumeric name="dei:PreCommencementTenderOffer" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:boolballotbox" id="ixv-371">&#9744;</ix:nonNumeric></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;text-align:left"><span style="white-space:nowrap">Pre-commencement</span> communications pursuant to Rule <span style="white-space:nowrap">14d-2(b)</span> under the Exchange Act (17 CFR <span style="white-space:nowrap">240.14d-2(b))</span></p></td></tr></table> <p style="font-size:6pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="border-collapse:collapse; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:4%;vertical-align:top;text-align:left"><ix:nonNumeric name="dei:PreCommencementIssuerTenderOffer" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:boolballotbox" id="ixv-372">&#9744;</ix:nonNumeric></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;text-align:left"><span style="white-space:nowrap">Pre-commencement</span> communications pursuant to Rule <span style="white-space:nowrap">13e-4(c)</span> under the Exchange Act (17 CFR <span style="white-space:nowrap">240.13e-</span> 4(c))</p></td></tr></table> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Securities registered pursuant to Section&#160;12(b) of the Act:</p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table cellspacing="0" cellpadding="0" style="border-collapse:collapse; font-family:Times New Roman; font-size:10pt;width:100%;border-spacing:0;margin:0 auto">
<tr>
<td style="width:34%"/>
<td style="vertical-align:bottom"/>
<td style="width:32%"/>
<td style="vertical-align:bottom;width:1%"/>
<td style="width:32%"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<td style="border-bottom:1.00pt solid #000000;vertical-align:bottom;white-space:nowrap;text-align:center"> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">Title of each class</p></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="border-bottom:1.00pt solid #000000;vertical-align:bottom;text-align:center"> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">Trading<br/>Symbol(s)</p></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="border-bottom:1.00pt solid #000000;vertical-align:bottom;text-align:center"> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">Name of each exchange<br/>on which registered</p></td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:Security12bTitle" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember" id="ixv-373">Common Stock, $0.0075 par value</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:TradingSymbol" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember" id="ixv-374">XOMA</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:SecurityExchangeName" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember" format="ixt-sec:exchnameen" id="ixv-375">The Nasdaq Global Market</ix:nonNumeric></td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:Security12bTitle" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" id="ixv-376">8.625% Series A Cumulative Perpetual Preferred Stock, par value $0.05 per share</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:TradingSymbol" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" id="ixv-377">XOMAP</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:SecurityExchangeName" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" format="ixt-sec:exchnameen" id="ixv-378">The Nasdaq Global Market</ix:nonNumeric></td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:Security12bTitle" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" id="ixv-379">Depositary Shares (each representing 1/1000th interest in a share of 8.375% Series B Cumulative Perpetual Preferred Stock, par value $0.05 per share)</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:TradingSymbol" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" id="ixv-380">XOMAO</ix:nonNumeric></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top;text-align:center"><ix:nonNumeric name="dei:SecurityExchangeName" contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" format="ixt-sec:exchnameen" id="ixv-381">The Nasdaq Global Market</ix:nonNumeric></td></tr></table> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR &#167;230.405) or Rule <span style="white-space:nowrap">12b-2</span> of the Securities Exchange Act of 1934 (17 CFR <span style="white-space:nowrap">&#167;240.12b-2).</span></p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Emerging growth company&#8194;<ix:nonNumeric name="dei:EntityEmergingGrowthCompany" contextRef="duration_2025-11-21_to_2025-11-21" format="ixt-sec:boolballotbox" id="ixv-382">&#9744;</ix:nonNumeric></p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section&#160;13(a) of the Exchange Act.&#8194;&#9744;</p> <p style="font-size:10pt;margin-top:0pt;margin-bottom:0pt">&#160;</p> <div style="line-height:1.0pt;margin-top:0pt;margin-bottom:0pt;border-bottom:1px solid #000000">&#160;</div> <div style="line-height:3.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1px solid #000000">&#160;</div></div></div>

<p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
<hr style="color:#999999;height:3px;width:100%;clear:both"/>

<div style="text-align:center"><div style="width:8.5in;text-align:left;margin-left: auto;margin-right: auto">

<table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:11%;vertical-align:top;text-align:left"><span style="font-weight:bold">Item&#8201;2.01</span></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:left">Completion of Acquisition or Disposition of Assets. </p></td></tr></table> <p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">As previously disclosed, XOMA Royalty Corporation (&#8220;<span style="text-decoration:underline">XOMA</span>&#8221;) entered into a share purchase agreement, dated August&#160;3, 2025 (as amended to date, the &#8220;<span style="text-decoration:underline">Purchase Agreement</span>&#8221;), with LAVA Therapeutics N.V., a public limited liability company (<span style="font-style:italic">naamloze vennootschap</span>) organized under the laws of The Netherlands (the &#8220;<span style="text-decoration:underline">LAVA</span>&#8221;). In accordance with the Purchase Agreement, on August&#160;15, 2025, XOMA commenced a tender offer (the &#8220;<span style="text-decoration:underline">Offer</span>&#8221;) to purchase all of LAVA&#8217;s issued and outstanding common shares, with a nominal value of &#8364;0.12 per share (&#8220;<span style="text-decoration:underline">Shares</span>&#8221;) for a price per Share of (i) $1.04 (the &#8220;<span style="text-decoration:underline">Cash Amount</span>&#8221;), payable subject to any applicable tax withholding and without interest, and (ii)&#160;one <span style="white-space:nowrap">non-transferable</span> contractual contingent value right (&#8220;<span style="text-decoration:underline">CVR</span>&#8221;) for each Share, which shall represent the right to receive potential payments, in cash, described in, and subject to and in accordance with the terms and conditions of, the CVR Agreement (as described below). Capitalized terms used and not otherwise defined in this Form <span style="white-space:nowrap">8-K</span> shall have the meanings assigned to such terms in the Offer to Purchase (as defined below). </p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Pursuant to the Purchase Agreement and the Amended and Restated Offer to Purchase, dated October&#160;17, 2025 (together with any subsequent amendments or supplements thereto, the &#8220;<span style="text-decoration:underline">Offer to Purchase</span>&#8221;), and upon the terms and subject to the conditions thereof, (i)&#160;the Subsequent Offering Period expired as scheduled, one minute after 11:59 p.m. Eastern Time on Thursday, November&#160;20, 2025 and (ii)&#160;XOMA and LAVA effectuated the Post-Offer Reorganization, which became effective on November&#160;20, 2025. Upon completion of those transactions, each LAVA shareholder that did not tender its Shares prior to the expiration of the Subsequent Offering Period ceased to hold any Shares and will receive, pursuant to the Post-Offer Reorganization, an amount in cash and CVRs, without interest and subject to any required tax withholding, equal to the Offer Consideration multiplied by the number of Shares held by such minority shareholder immediately prior to the effective time of the Downstream Merger. </p> <p style="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The foregoing descriptions of the Purchase Agreement, the CVR Agreement and the transactions contemplated thereby do not purport to be complete and are qualified in their entirety by reference to the Purchase Agreement and the CVR Agreement, copies of which are filed as Exhibit 2.1, Exhibit 2.2 and Exhibit 2.3 to this Current Report on Form <span style="white-space:nowrap">8-K</span> and are incorporated by reference herein. </p> <p style="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:11%;vertical-align:top;text-align:left"><span style="font-weight:bold">Item&#8201;8.01</span></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:left">Other Events. </p></td></tr></table> <p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">On November&#160;21, 2025, XOMA issued a press release announcing the expiration of the Subsequent Offering Period and effectuation of the Post-Offer Reorganization. The full text of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. </p> <p style="font-size:18pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt;border-spacing:0;width:100%" cellpadding="0" cellspacing="0">
<tr style="page-break-inside:avoid">
<td style="width:11%;vertical-align:top;text-align:left"><span style="font-weight:bold">Item&#8201;9.01</span></td>
<td style="vertical-align:top;text-align:left"> <p style=" margin-top:0pt ; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:left">Financial Statements and Exhibits. </p></td></tr></table> <p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold"><span style="font-style:italic">(a) Financial Statements of Business Acquired. </span></p> <p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The financial statements of LAVA and related notes as of and for the years ended December&#160;31, 2024 and 2023 and the unaudited financial statements of LAVA as of September&#160;30, 2025 and 2024 and for the periods then ended and related notes will be included in an exhibit that will be filed in an amendment to this Current Report on Form <span style="white-space:nowrap">8-K</span> within the period specified in Item 9.01(a)(3) of Form <span style="white-space:nowrap">8-K.</span> </p> <p style="margin-top:18pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold"><span style="font-style:italic">(b) Pro Forma Financial Information. </span></p> <p style="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">The unaudited pro forma condensed combined financial information of XOMA and LAVA as of and for the nine months ended September&#160;30, 2025 and the year ended December&#160;31, 2024 and the related notes will be included in an exhibit that will be filed in an amendment to this Current Report on Form <span style="white-space:nowrap">8-K</span> within the period specified in Item 9.01(a)(3) of Form <span style="white-space:nowrap">8-K.</span> </p> <p style="font-size:18pt; margin-top:0pt; margin-bottom:0pt">&#160;</p>
</div></div>



<p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
<hr style="color:#999999;height:3px;width:100%;clear:both"/>

<div style="text-align:center"><div style="width:8.5in;text-align:left;margin-left: auto;margin-right: auto">
 <p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold"><span style="font-style:italic">(d)&#8195;Exhibits. </span></p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table cellspacing="0" cellpadding="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt;width:100%;border-spacing:0;margin:0 auto">


<tr>

<td/>

<td style="vertical-align:bottom;width:7%"/>
<td style="width:90%"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:8pt">
<td style="vertical-align:bottom;white-space:nowrap;text-align:center"> <p style=" margin-top:0pt ; margin-bottom:0pt; border-bottom:1.00pt solid #000000; display:inline-block; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">Exhibit&#160;No.</p></td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="border-bottom:1.00pt solid #000000;vertical-align:bottom;white-space:nowrap;text-align:center"> <p style="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman;font-weight:bold;text-align:center">Description</p></td></tr>


<tr style="font-size:1pt">
<td style="height:6pt"/>
<td style="height:6pt" colspan="2"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;white-space:nowrap">2.1</td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="vertical-align:top"><a href="http://www.sec.gov/Archives/edgar/data/1840748/000110465925073374/tm2522230d1_ex2-1.htm">Share Purchase Agreement, by and among XOMA Royalty Corporation and LAVA Therapeutics N.V., dated August&#160;3, 2025 (incorporated by reference to Exhibit&#160;2.1 to LAVA&#8217;s Current Report on Form <span style="white-space:nowrap">8-K</span> filed with the SEC on August&#160;4, 2025). </a></td></tr>
<tr style="font-size:1pt">
<td style="height:6pt"/>
<td style="height:6pt" colspan="2"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;white-space:nowrap">2.2</td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="vertical-align:top"><a href="http://www.sec.gov/Archives/edgar/data/1840748/000110465925100317/tm2528774d1_ex2-1.htm">Amendment to Share Purchase Agreement, by and among XOMA Royalty Corporation and LAVA Therapeutics N.V., dated October&#160;17, 2025 (incorporated by reference to Exhibit&#160;2.1 to LAVA&#8217;s Current Report on <span style="white-space:nowrap">Form&#160;8-K</span> filed with the SEC on October&#160;17, 2025). </a></td></tr>
<tr style="font-size:1pt">
<td style="height:6pt"/>
<td style="height:6pt" colspan="2"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;white-space:nowrap">2.3</td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="vertical-align:top"><a href="http://www.sec.gov/Archives/edgar/data/1840748/000110465925100317/tm2528774d1_ex2-1.htm">Form of Contingent Value Rights Agreement (incorporated herein by reference to Exhibit C of Exhibit&#160;2.1 to LAVA&#8217;s Current Report on Form <span style="white-space:nowrap">8-K</span> filed with the SEC on October&#160;17, 2025). </a></td></tr>
<tr style="font-size:1pt">
<td style="height:6pt"/>
<td style="height:6pt" colspan="2"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;white-space:nowrap">99.1</td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="vertical-align:top"><a href="http://www.sec.gov/Archives/edgar/data/791908/000119312525290606/d62624dex99a5d.htm">Press Release issued by XOMA Royalty Corporation on November&#160;21, 2025 (incorporated herein by reference to Exhibit (a)(5)(D) to the Schedule <span style="white-space:nowrap">TO-T/A</span> filed by XOMA Royalty Corporation on November&#160;21, 2025).</a></td></tr>
<tr style="font-size:1pt">
<td style="height:6pt"/>
<td style="height:6pt" colspan="2"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:top;white-space:nowrap">104</td>
<td style="vertical-align:bottom">&#160;&#160;</td>
<td style="vertical-align:top">Cover Page Interactive Data File (embedded within the Inline XBRL document).</td></tr>
</table> <p style="font-size:18pt; margin-top:0pt; margin-bottom:0pt">&#160;</p>
</div></div>



<p style="margin-top:1em; margin-bottom:0em; page-break-before:always"> </p>
<hr style="color:#999999;height:3px;width:100%;clear:both"/>

<div style="text-align:center"><div style="width:8.5in;text-align:left;margin-left: auto;margin-right: auto">
 <p style="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman;font-weight:bold;text-align:center">SIGNATURES </p> <p style="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. </p> <p style="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&#160;</p>
<table cellspacing="0" cellpadding="0" style="BORDER-COLLAPSE:COLLAPSE; font-family:Times New Roman; font-size:10pt;width:100%;border-spacing:0">


<tr>

<td style="width:44%"/>

<td style="vertical-align:bottom;width:1%"/>
<td style="width:4%"/>

<td style="vertical-align:bottom"/>
<td style="width:5%"/>

<td style="vertical-align:bottom;width:1%"/>
<td style="width:44%"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom" colspan="5"><span style="font-weight:bold">XOMA ROYALTY CORPORATION</span></td></tr>


<tr style="font-size:1pt">
<td style="height:12pt"/>
<td style="height:12pt" colspan="2"/>
<td style="height:12pt" colspan="4"/></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:bottom">Date: November&#160;21, 2025</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top">By:</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom" colspan="3"> <p style="margin-top:0pt; margin-bottom:1pt; border-bottom:1px solid #000000; font-size:10pt; font-family:Times New Roman">/s/ Owen Hughes</p></td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top"><span style="font-weight:bold">Name:</span></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">Owen Hughes</td></tr>
<tr style="page-break-inside:avoid ; font-family:Times New Roman; font-size:10pt">
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:top"><span style="font-weight:bold">Title:</span></td>
<td style="vertical-align:bottom">&#160;</td>
<td style="vertical-align:bottom">Chief Executive Officer</td></tr>
</table>
</div></div>

</body></html>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.SCH
<SEQUENCE>2
<FILENAME>xoma-20251121.xsd
<DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA
<TEXT>
<XBRL>
<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN - https://www.dfinsolutions.com/ -->
<!-- CTU Version: Release 2512 Build:20250722.1 -->
<!-- Creation date: 11/21/2025 5:58:54 PM Eastern Time -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema
  xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric"
  xmlns:num="http://www.xbrl.org/dtr/type/numeric"
  xmlns:us-types="http://fasb.org/us-types/2025"
  xmlns:xoma="http://www.xoma.com/20251121"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:xbrli="http://www.xbrl.org/2003/instance"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xbrldt="http://xbrl.org/2005/xbrldt"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  attributeFormDefault="unqualified"
  elementFormDefault="qualified"
  targetNamespace="http://www.xoma.com/20251121"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance" />
    <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase" />
    <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd" namespace="http://xbrl.sec.gov/dei/2025" />
    <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/numeric" />
    <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/non-numeric" />
    <xsd:import schemaLocation="https://xbrl.sec.gov/naics/2025/naics-2025.xsd" namespace="http://xbrl.sec.gov/naics/2025" />
    <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt" />
    <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd" namespace="http://fasb.org/us-gaap/2025" />
    <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-types-2025.xsd" namespace="http://fasb.org/us-types/2025" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="xoma-20251121_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Label Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="xoma-20251121_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="xoma-20251121_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="xoma_DocumentAndEntityInformationTable" name="DocumentAndEntityInformationTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="xoma_DocumentAndEntityInformationLineItems" name="DocumentAndEntityInformationLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" name="M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" name="DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
</xsd:schema>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.DEF
<SEQUENCE>3
<FILENAME>xoma-20251121_def.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION DEFINITION LINKBASE
<TEXT>
<XBRL>
<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN - https://www.dfinsolutions.com/ -->
<!-- CTU Version: Release 2512 Build:20250722.1 -->
<!-- Creation date: 11/21/2025 5:58:56 PM Eastern Time -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <link:roleRef roleURI="http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation" xlink:href="xoma-20251121.xsd#Role_DocumentDocumentAndEntityInformation" xlink:type="simple" />
  <link:definitionLink xlink:type="extended" xlink:role="http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation">
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationTable" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationTable" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationLineItems" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationLineItems" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis" xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain_2" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName" xlink:type="locator" xlink:label="dei_EntityRegistrantName" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag" xlink:type="locator" xlink:label="dei_AmendmentFlag" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey" xlink:type="locator" xlink:label="dei_EntityCentralIndexKey" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType" xlink:type="locator" xlink:label="dei_DocumentType" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate" xlink:type="locator" xlink:label="dei_DocumentPeriodEndDate" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode" xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber" xlink:type="locator" xlink:label="dei_EntityFileNumber" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber" xlink:type="locator" xlink:label="dei_EntityTaxIdentificationNumber" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine1" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine2" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown" xlink:type="locator" xlink:label="dei_EntityAddressCityOrTown" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince" xlink:type="locator" xlink:label="dei_EntityAddressStateOrProvince" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode" xlink:type="locator" xlink:label="dei_EntityAddressPostalZipCode" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode" xlink:type="locator" xlink:label="dei_CityAreaCode" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber" xlink:type="locator" xlink:label="dei_LocalPhoneNumber" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications" xlink:type="locator" xlink:label="dei_WrittenCommunications" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial" xlink:type="locator" xlink:label="dei_SolicitingMaterial" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementTenderOffer" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementIssuerTenderOffer" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle" xlink:type="locator" xlink:label="dei_Security12bTitle" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol" xlink:type="locator" xlink:label="dei_TradingSymbol" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName" xlink:type="locator" xlink:label="dei_SecurityExchangeName" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany" xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="xoma_DocumentAndEntityInformationTable" order="1" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="xoma_DocumentAndEntityInformationTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="1" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="23" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain_2" order="23.0001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="us-gaap_CommonStockMember" order="24" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" order="25" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" order="26" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityRegistrantName" order="28.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_AmendmentFlag" order="29.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityCentralIndexKey" order="30.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_DocumentType" order="34.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_DocumentPeriodEndDate" order="35.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityIncorporationStateCountryCode" order="36.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityFileNumber" order="37.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityTaxIdentificationNumber" order="38.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressAddressLine1" order="39.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressAddressLine2" order="40.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressCityOrTown" order="41.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressStateOrProvince" order="42.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressPostalZipCode" order="43.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_CityAreaCode" order="44.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_LocalPhoneNumber" order="45.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_WrittenCommunications" order="46.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_SolicitingMaterial" order="47.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_PreCommencementTenderOffer" order="48.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_PreCommencementIssuerTenderOffer" order="49.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_Security12bTitle" order="50.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_TradingSymbol" order="51.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_SecurityExchangeName" order="52.001" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityEmergingGrowthCompany" order="53.001" priority="2" use="optional" />
  </link:definitionLink>
</linkbase>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.LAB
<SEQUENCE>4
<FILENAME>xoma-20251121_lab.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE
<TEXT>
<XBRL>
<?xml version="1.0" encoding="us-ascii" standalone="yes"?>
<!-- DFIN - https://www.dfinsolutions.com/ -->
<!-- CTU Version: Release 2512 Build:20250722.1 -->
<!-- Creation date: 11/21/2025 5:58:54 PM Eastern Time -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<link:linkbase
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract" xlink:type="locator" xlink:label="dei_CoverAbstract" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CoverAbstract" xlink:to="dei_CoverAbstract_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_CoverAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_CoverAbstract_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cover [Abstract]</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName" xlink:type="locator" xlink:label="dei_EntityRegistrantName" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityRegistrantName" xlink:to="dei_EntityRegistrantName_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityRegistrantName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag" xlink:type="locator" xlink:label="dei_AmendmentFlag" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_AmendmentFlag" xlink:to="dei_AmendmentFlag_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_AmendmentFlag_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey" xlink:type="locator" xlink:label="dei_EntityCentralIndexKey" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityCentralIndexKey" xlink:to="dei_EntityCentralIndexKey_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType" xlink:type="locator" xlink:label="dei_DocumentType" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentType" xlink:to="dei_DocumentType_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_DocumentType_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Type</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate" xlink:type="locator" xlink:label="dei_DocumentPeriodEndDate" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_DocumentPeriodEndDate" xlink:to="dei_DocumentPeriodEndDate_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode" xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityIncorporationStateCountryCode" xlink:to="dei_EntityIncorporationStateCountryCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Incorporation State Country Code</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Incorporation State Country Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber" xlink:type="locator" xlink:label="dei_EntityFileNumber" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityFileNumber" xlink:to="dei_EntityFileNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity File Number</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityFileNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity File Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber" xlink:type="locator" xlink:label="dei_EntityTaxIdentificationNumber" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityTaxIdentificationNumber" xlink:to="dei_EntityTaxIdentificationNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Tax Identification Number</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Tax Identification Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine1" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressAddressLine1" xlink:to="dei_EntityAddressAddressLine1_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine2" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressAddressLine2" xlink:to="dei_EntityAddressAddressLine2_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine2_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line Two</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressAddressLine2_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line Two</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown" xlink:type="locator" xlink:label="dei_EntityAddressCityOrTown" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressCityOrTown" xlink:to="dei_EntityAddressCityOrTown_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince" xlink:type="locator" xlink:label="dei_EntityAddressStateOrProvince" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressStateOrProvince" xlink:to="dei_EntityAddressStateOrProvince_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode" xlink:type="locator" xlink:label="dei_EntityAddressPostalZipCode" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityAddressPostalZipCode" xlink:to="dei_EntityAddressPostalZipCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode" xlink:type="locator" xlink:label="dei_CityAreaCode" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_CityAreaCode" xlink:to="dei_CityAreaCode_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_CityAreaCode_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber" xlink:type="locator" xlink:label="dei_LocalPhoneNumber" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_LocalPhoneNumber" xlink:to="dei_LocalPhoneNumber_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Local Phone Number</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_LocalPhoneNumber_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Local Phone Number</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications" xlink:type="locator" xlink:label="dei_WrittenCommunications" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_WrittenCommunications" xlink:to="dei_WrittenCommunications_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_WrittenCommunications_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Written Communications</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_WrittenCommunications_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Written Communications</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial" xlink:type="locator" xlink:label="dei_SolicitingMaterial" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_SolicitingMaterial" xlink:to="dei_SolicitingMaterial_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_SolicitingMaterial_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Soliciting Material</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_SolicitingMaterial_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Soliciting Material</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementTenderOffer" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_PreCommencementTenderOffer" xlink:to="dei_PreCommencementTenderOffer_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_PreCommencementTenderOffer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Pre Commencement Tender Offer</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_PreCommencementTenderOffer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pre Commencement Tender Offer</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementIssuerTenderOffer" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_PreCommencementIssuerTenderOffer" xlink:to="dei_PreCommencementIssuerTenderOffer_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_PreCommencementIssuerTenderOffer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Pre Commencement Issuer Tender Offer</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_PreCommencementIssuerTenderOffer_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pre Commencement Issuer Tender Offer</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle" xlink:type="locator" xlink:label="dei_Security12bTitle" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_Security12bTitle" xlink:to="dei_Security12bTitle_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Security 12b Title</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_Security12bTitle_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security 12b Title</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol" xlink:type="locator" xlink:label="dei_TradingSymbol" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_TradingSymbol" xlink:to="dei_TradingSymbol_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_TradingSymbol_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Trading Symbol</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName" xlink:type="locator" xlink:label="dei_SecurityExchangeName" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_SecurityExchangeName" xlink:to="dei_SecurityExchangeName_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_SecurityExchangeName_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany" xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityEmergingGrowthCompany" xlink:to="dei_EntityEmergingGrowthCompany_lbl" />
    <link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Entity Emerging Growth Company</link:label>
    <link:label xml:lang="en-US" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Emerging Growth Company</link:label>
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationTable" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationTable" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xoma_DocumentAndEntityInformationTable" xlink:to="xoma_DocumentAndEntityInformationTable_lbl" />
    <link:label xml:lang="en-US" xlink:label="xoma_DocumentAndEntityInformationTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document And Entity Information [Table]</link:label>
    <link:label xml:lang="en-US" xlink:label="xoma_DocumentAndEntityInformationTable_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document And Entity Information [Table]</link:label>
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationLineItems" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationLineItems" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="xoma_DocumentAndEntityInformationLineItems_lbl" />
    <link:label xml:lang="en-US" xlink:label="xoma_DocumentAndEntityInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Document And Entity Information [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:label="xoma_DocumentAndEntityInformationLineItems_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document And Entity Information [Line Items]</link:label>
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis" xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_StatementClassOfStockAxis_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Stock [Axis]</link:label>
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="us-gaap_ClassOfStockDomain_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_ClassOfStockDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_ClassOfStockDomain_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Stock [Domain]</link:label>
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockMember" xlink:to="us-gaap_CommonStockMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="us-gaap_CommonStockMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock [Member]</link:label>
    <link:loc xlink:href="xoma-20251121.xsd#xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:to="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">M 8.625 Series A Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">M 8.625 Series A Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</link:label>
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:to="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" />
    <link:label xml:lang="en-US" xlink:label="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label">Depositary Shares Each Representing 11000th Interest In A Share Of 8.375 Series B Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</link:label>
    <link:label xml:lang="en-US" xlink:label="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember_lbl" xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depositary Shares Each Representing 11000th Interest In A Share Of 8.375 Series B Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</link:label>
  </link:labelLink>
</link:linkbase>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-101.PRE
<SEQUENCE>5
<FILENAME>xoma-20251121_pre.xml
<DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE
<TEXT>
<XBRL>
<?xml version="1.0" encoding="us-ascii" standalone="yes"?>
<!-- DFIN - https://www.dfinsolutions.com/ -->
<!-- CTU Version: Release 2512 Build:20250722.1 -->
<!-- Creation date: 11/21/2025 5:58:54 PM Eastern Time -->
<!-- Copyright (c) 2025 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<link:linkbase
    xmlns:link="http://www.xbrl.org/2003/linkbase"
    xmlns:xlink="http://www.w3.org/1999/xlink"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xbrldt="http://xbrl.org/2005/xbrldt"
    xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation" xlink:href="xoma-20251121.xsd#Role_DocumentDocumentAndEntityInformation" xlink:type="simple" />
  <link:presentationLink xlink:type="extended" xlink:role="http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation">
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CoverAbstract" xlink:type="locator" xlink:label="dei_CoverAbstract" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationTable" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationTable" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_CoverAbstract" xlink:to="xoma_DocumentAndEntityInformationTable" order="21" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DocumentAndEntityInformationLineItems" xlink:type="locator" xlink:label="xoma_DocumentAndEntityInformationLineItems" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationTable" xlink:to="xoma_DocumentAndEntityInformationLineItems" order="22" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementClassOfStockAxis" xlink:type="locator" xlink:label="us-gaap_StatementClassOfStockAxis" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationTable" xlink:to="us-gaap_StatementClassOfStockAxis" order="1" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:type="locator" xlink:label="us-gaap_ClassOfStockDomain" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis" xlink:to="us-gaap_ClassOfStockDomain" order="23" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="us-gaap_CommonStockMember" order="24" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember" order="25" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="xoma-20251121.xsd#xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" xlink:type="locator" xlink:label="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember" order="26" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName" xlink:type="locator" xlink:label="dei_EntityRegistrantName" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityRegistrantName" order="28.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag" xlink:type="locator" xlink:label="dei_AmendmentFlag" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_AmendmentFlag" order="29.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey" xlink:type="locator" xlink:label="dei_EntityCentralIndexKey" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityCentralIndexKey" order="30.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType" xlink:type="locator" xlink:label="dei_DocumentType" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_DocumentType" order="34.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate" xlink:type="locator" xlink:label="dei_DocumentPeriodEndDate" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_DocumentPeriodEndDate" order="35.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode" xlink:type="locator" xlink:label="dei_EntityIncorporationStateCountryCode" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityIncorporationStateCountryCode" order="36.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber" xlink:type="locator" xlink:label="dei_EntityFileNumber" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityFileNumber" order="37.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber" xlink:type="locator" xlink:label="dei_EntityTaxIdentificationNumber" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityTaxIdentificationNumber" order="38.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine1" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressAddressLine1" order="39.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine2" xlink:type="locator" xlink:label="dei_EntityAddressAddressLine2" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressAddressLine2" order="40.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown" xlink:type="locator" xlink:label="dei_EntityAddressCityOrTown" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressCityOrTown" order="41.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince" xlink:type="locator" xlink:label="dei_EntityAddressStateOrProvince" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressStateOrProvince" order="42.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode" xlink:type="locator" xlink:label="dei_EntityAddressPostalZipCode" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityAddressPostalZipCode" order="43.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode" xlink:type="locator" xlink:label="dei_CityAreaCode" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_CityAreaCode" order="44.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber" xlink:type="locator" xlink:label="dei_LocalPhoneNumber" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_LocalPhoneNumber" order="45.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications" xlink:type="locator" xlink:label="dei_WrittenCommunications" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_WrittenCommunications" order="46.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial" xlink:type="locator" xlink:label="dei_SolicitingMaterial" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_SolicitingMaterial" order="47.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementTenderOffer" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_PreCommencementTenderOffer" order="48.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer" xlink:type="locator" xlink:label="dei_PreCommencementIssuerTenderOffer" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_PreCommencementIssuerTenderOffer" order="49.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_Security12bTitle" xlink:type="locator" xlink:label="dei_Security12bTitle" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_Security12bTitle" order="50.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_TradingSymbol" xlink:type="locator" xlink:label="dei_TradingSymbol" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_TradingSymbol" order="51.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SecurityExchangeName" xlink:type="locator" xlink:label="dei_SecurityExchangeName" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_SecurityExchangeName" order="52.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <link:loc xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany" xlink:type="locator" xlink:label="dei_EntityEmergingGrowthCompany" />
    <link:presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="xoma_DocumentAndEntityInformationLineItems" xlink:to="dei_EntityEmergingGrowthCompany" order="53.001" priority="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
  </link:presentationLink>
</link:linkbase>
</XBRL>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>7
<FILENAME>R1.htm
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<html>
<head>
<title></title>
<link rel="stylesheet" type="text/css" href="include/report.css">
<script type="text/javascript" src="Show.js">/* Do Not Remove This Comment */</script><script type="text/javascript">
							function toggleNextSibling (e) {
							if (e.nextSibling.style.display=='none') {
							e.nextSibling.style.display='block';
							} else { e.nextSibling.style.display='none'; }
							}</script>
</head>
<body>
<span style="display: none;">v3.25.3</span><table class="report" border="0" cellspacing="2" id="id2">
<tr>
<th class="tl" colspan="1" rowspan="1"><div style="width: 200px;"><strong>Document and Entity Information<br></strong></div></th>
<th class="th"><div>Nov. 21, 2025</div></th>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_xoma_DocumentAndEntityInformationLineItems', window );"><strong>Document And Entity Information [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityRegistrantName', window );">Entity Registrant Name</a></td>
<td class="text">XOMA Royalty Corp<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_AmendmentFlag', window );">Amendment Flag</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityCentralIndexKey', window );">Entity Central Index Key</a></td>
<td class="text">0000791908<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_DocumentType', window );">Document Type</a></td>
<td class="text">8-K<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_DocumentPeriodEndDate', window );">Document Period End Date</a></td>
<td class="text">Nov. 21,  2025<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityIncorporationStateCountryCode', window );">Entity Incorporation State Country Code</a></td>
<td class="text">NV<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityFileNumber', window );">Entity File Number</a></td>
<td class="text">001-39801<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityTaxIdentificationNumber', window );">Entity Tax Identification Number</a></td>
<td class="text">52-2154066<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityAddressAddressLine1', window );">Entity Address, Address Line One</a></td>
<td class="text">2200 Powell Street<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityAddressAddressLine2', window );">Entity Address, Address Line Two</a></td>
<td class="text">Suite 310<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityAddressCityOrTown', window );">Entity Address, City or Town</a></td>
<td class="text">Emeryville<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityAddressStateOrProvince', window );">Entity Address, State or Province</a></td>
<td class="text">CA<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityAddressPostalZipCode', window );">Entity Address, Postal Zip Code</a></td>
<td class="text">94608<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_CityAreaCode', window );">City Area Code</a></td>
<td class="text">(510)<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_LocalPhoneNumber', window );">Local Phone Number</a></td>
<td class="text">204-7200<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_WrittenCommunications', window );">Written Communications</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_SolicitingMaterial', window );">Soliciting Material</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_PreCommencementTenderOffer', window );">Pre Commencement Tender Offer</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_PreCommencementIssuerTenderOffer', window );">Pre Commencement Issuer Tender Offer</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_EntityEmergingGrowthCompany', window );">Entity Emerging Growth Company</a></td>
<td class="text">false<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember', window );">Common Stock [Member]</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_xoma_DocumentAndEntityInformationLineItems', window );"><strong>Document And Entity Information [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_Security12bTitle', window );">Security 12b Title</a></td>
<td class="text">Common Stock, $0.0075 par value<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_TradingSymbol', window );">Trading Symbol</a></td>
<td class="text">XOMA<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_SecurityExchangeName', window );">Security Exchange Name</a></td>
<td class="text">NASDAQ<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_us-gaap_StatementClassOfStockAxis=xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember', window );">M 8.625 Series A Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_xoma_DocumentAndEntityInformationLineItems', window );"><strong>Document And Entity Information [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_Security12bTitle', window );">Security 12b Title</a></td>
<td class="text">8.625% Series A Cumulative Perpetual Preferred Stock, par value $0.05 per share<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_TradingSymbol', window );">Trading Symbol</a></td>
<td class="text">XOMAP<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_SecurityExchangeName', window );">Security Exchange Name</a></td>
<td class="text">NASDAQ<span></span>
</td>
</tr>
<tr class="rh">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_us-gaap_StatementClassOfStockAxis=xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember', window );">Depositary Shares Each Representing 11000th Interest In A Share Of 8.375 Series B Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]</a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_xoma_DocumentAndEntityInformationLineItems', window );"><strong>Document And Entity Information [Line Items]</strong></a></td>
<td class="text">&#160;<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_Security12bTitle', window );">Security 12b Title</a></td>
<td class="text">Depositary Shares (each representing 1/1000th interest in a share of 8.375% Series B Cumulative Perpetual Preferred Stock, par value $0.05 per share)<span></span>
</td>
</tr>
<tr class="re">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_TradingSymbol', window );">Trading Symbol</a></td>
<td class="text">XOMAO<span></span>
</td>
</tr>
<tr class="ro">
<td class="pl" style="border-bottom: 0px;" valign="top"><a class="a" href="javascript:void(0);" onclick="Show.showAR( this, 'defref_dei_SecurityExchangeName', window );">Security Exchange Name</a></td>
<td class="text">NASDAQ<span></span>
</td>
</tr>
</table>
<div style="display: none;">
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_AmendmentFlag">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_AmendmentFlag</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_CityAreaCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Area code of city</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_CityAreaCode</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentPeriodEndDate">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentPeriodEndDate</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:dateItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_DocumentType">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_DocumentType</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:submissionTypeItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressAddressLine1">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Address Line 1 such as Attn, Building Name, Street Name</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressAddressLine1</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressAddressLine2">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Address Line 2 such as Street or Suite number</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressAddressLine2</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressCityOrTown">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Name of the City or Town</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressCityOrTown</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressPostalZipCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Code for the postal or zip code</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressPostalZipCode</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityAddressStateOrProvince">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Name of the state or province.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityAddressStateOrProvince</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:stateOrProvinceItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityCentralIndexKey">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityCentralIndexKey</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:centralIndexKeyItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityEmergingGrowthCompany">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Indicate if registrant meets the emerging growth company criteria.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityEmergingGrowthCompany</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityFileNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityFileNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:fileNumberItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityIncorporationStateCountryCode">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Two-character EDGAR code representing the state or country of incorporation.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityIncorporationStateCountryCode</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:edgarStateCountryItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityRegistrantName">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityRegistrantName</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_EntityTaxIdentificationNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b-2<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_EntityTaxIdentificationNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:employerIdItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_LocalPhoneNumber">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Local phone number for entity.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_LocalPhoneNumber</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:normalizedStringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_PreCommencementIssuerTenderOffer">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 13e<br> -Subsection 4c<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_PreCommencementIssuerTenderOffer</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_PreCommencementTenderOffer">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 14d<br> -Subsection 2b<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_PreCommencementTenderOffer</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_Security12bTitle">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Title of a 12(b) registered security.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection b<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_Security12bTitle</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:securityTitleItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_SecurityExchangeName">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Name of the Exchange on which a security is registered.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 12<br> -Subsection d1-1<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_SecurityExchangeName</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:edgarExchangeCodeItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_SolicitingMaterial">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Exchange Act<br> -Number 240<br> -Section 14a<br> -Subsection 12<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_SolicitingMaterial</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_TradingSymbol">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Trading symbol of an instrument as listed on an exchange.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_TradingSymbol</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>dei:tradingSymbolItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_dei_WrittenCommunications">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Definition</a><div><p>Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ References</a><div style="display: none;"><p>Reference 1: http://www.xbrl.org/2003/role/presentationRef<br> -Publisher SEC<br> -Name Securities Act<br> -Number 230<br> -Section 425<br></p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">dei_WrittenCommunications</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>dei_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:booleanItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_xoma_DocumentAndEntityInformationLineItems">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- References</a><div><p>No definition available.</p></div>
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">+ Details</a><div style="display: none;"><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">xoma_DocumentAndEntityInformationLineItems</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td>xoma_</td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>xbrli:stringItemType</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td>duration</td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementClassOfStockAxis=xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementClassOfStockAxis=xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
<table border="0" cellpadding="0" cellspacing="0" class="authRefData" style="display: none;" id="defref_us-gaap_StatementClassOfStockAxis=xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember">
<tr><td class="hide"><a style="color: white;" href="javascript:void(0);" onclick="Show.hideAR();">X</a></td></tr>
<tr><td><div class="body" style="padding: 2px;">
<a href="javascript:void(0);" onclick="Show.toggleNext( this );">- Details</a><div><table border="0" cellpadding="0" cellspacing="0">
<tr>
<td><strong> Name:</strong></td>
<td style="white-space:nowrap;">us-gaap_StatementClassOfStockAxis=xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember</td>
</tr>
<tr>
<td style="padding-right: 4px;white-space:nowrap;"><strong> Namespace Prefix:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Data Type:</strong></td>
<td>na</td>
</tr>
<tr>
<td><strong> Balance Type:</strong></td>
<td></td>
</tr>
<tr>
<td><strong> Period Type:</strong></td>
<td></td>
</tr>
</table></div>
</div></td></tr>
</table>
</div>
</body>
</html>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>8
<FILENAME>Show.js
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
// Edgar(tm) Renderer was created by staff of the U.S. Securities and Exchange Commission.  Data and content created by government employees within the scope of their employment are not subject to domestic copyright protection. 17 U.S.C. 105.
var Show={};Show.LastAR=null,Show.showAR=function(a,r,w){if(Show.LastAR)Show.hideAR();var e=a;while(e&&e.nodeName!='TABLE')e=e.nextSibling;if(!e||e.nodeName!='TABLE'){var ref=((window)?w.document:document).getElementById(r);if(ref){e=ref.cloneNode(!0);
e.removeAttribute('id');a.parentNode.appendChild(e)}}
if(e)e.style.display='block';Show.LastAR=e};Show.hideAR=function(){Show.LastAR.style.display='none'};Show.toggleNext=function(a){var e=a;while(e.nodeName!='DIV')e=e.nextSibling;if(!e.style){}else if(!e.style.display){}else{var d,p_;if(e.style.display=='none'){d='block';p='-'}else{d='none';p='+'}
e.style.display=d;if(a.textContent){a.textContent=p+a.textContent.substring(1)}else{a.innerText=p+a.innerText.substring(1)}}}
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>9
<FILENAME>report.css
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
/* Updated 2009-11-04 */
/* v2.2.0.24 */

/* DefRef Styles */
.report table.authRefData{
	background-color: #def;
	border: 2px solid #2F4497;
	font-size: 1em;
	position: absolute;
}

.report table.authRefData a {
	display: block;
	font-weight: bold;
}

.report table.authRefData p {
	margin-top: 0px;
}

.report table.authRefData .hide {
	background-color: #2F4497;
	padding: 1px 3px 0px 0px;
	text-align: right;
}

.report table.authRefData .hide a:hover {
	background-color: #2F4497;
}

.report table.authRefData .body {
	height: 150px;
	overflow: auto;
	width: 400px;
}

.report table.authRefData table{
	font-size: 1em;
}

/* Report Styles */
.pl a, .pl a:visited {
	color: black;
	text-decoration: none;
}

/* table */
.report {
	background-color: white;
	border: 2px solid #acf;
	clear: both;
	color: black;
	font: normal 8pt Helvetica, Arial, san-serif;
	margin-bottom: 2em;
}

.report hr {
	border: 1px solid #acf;
}

/* Top labels */
.report th {
	background-color: #acf;
	color: black;
	font-weight: bold;
	text-align: center;
}

.report th.void	{
	background-color: transparent;
	color: #000000;
	font: bold 10pt Helvetica, Arial, san-serif;
	text-align: left;
}

.report .pl {
	text-align: left;
	vertical-align: top;
	white-space: normal;
	width: 200px;
	white-space: normal; /* word-wrap: break-word; */
}

.report td.pl a.a {
	cursor: pointer;
	display: block;
	width: 200px;
	overflow: hidden;
}

.report td.pl div.a {
	width: 200px;
}

.report td.pl a:hover {
	background-color: #ffc;
}

/* Header rows... */
.report tr.rh {
	background-color: #acf;
	color: black;
	font-weight: bold;
}

/* Calendars... */
.report .rc {
	background-color: #f0f0f0;
}

/* Even rows... */
.report .re, .report .reu {
	background-color: #def;
}

.report .reu td {
	border-bottom: 1px solid black;
}

/* Odd rows... */
.report .ro, .report .rou {
	background-color: white;
}

.report .rou td {
	border-bottom: 1px solid black;
}

.report .rou table td, .report .reu table td {
	border-bottom: 0px solid black;
}

/* styles for footnote marker */
.report .fn {
	white-space: nowrap;
}

/* styles for numeric types */
.report .num, .report .nump {
	text-align: right;
	white-space: nowrap;
}

.report .nump {
	padding-left: 2em;
}

.report .nump {
	padding: 0px 0.4em 0px 2em;
}

/* styles for text types */
.report .text {
	text-align: left;
	white-space: normal;
}

.report .text .big {
	margin-bottom: 1em;
	width: 17em;
}

.report .text .more {
	display: none;
}

.report .text .note {
	font-style: italic;
	font-weight: bold;
}

.report .text .small {
	width: 10em;
}

.report sup {
	font-style: italic;
}

.report .outerFootnotes {
	font-size: 1em;
}
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>11
<FILENAME>FilingSummary.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<XML>
<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.3</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>4</ContextCount>
  <ElementCount>23</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>3</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>0</UnitCount>
  <MyReports>
    <Report instance="d65279d8k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="8-K" isOnlyDei="true" isUsgaap="true" original="d65279d8k.htm">d65279d8k.htm</File>
    <File>xoma-20251121.xsd</File>
    <File>xoma-20251121_def.xml</File>
    <File>xoma-20251121_lab.xml</File>
    <File>xoma-20251121_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>JSON
<SEQUENCE>14
<FILENAME>MetaLinks.json
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
{
 "version": "2.2",
 "instance": {
  "d65279d8k.htm": {
   "nsprefix": "xoma",
   "nsuri": "http://www.xoma.com/20251121",
   "dts": {
    "inline": {
     "local": [
      "d65279d8k.htm"
     ]
    },
    "schema": {
     "local": [
      "xoma-20251121.xsd"
     ],
     "remote": [
      "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xl-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xlink-2003-12-31.xsd",
      "http://www.xbrl.org/2005/xbrldt-2005.xsd",
      "http://www.xbrl.org/2006/ref-2006-02-27.xsd",
      "http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd",
      "http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd",
      "https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd",
      "https://www.xbrl.org/dtr/type/2020-01-21/types.xsd",
      "https://www.xbrl.org/dtr/type/2024-01-31/types.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-roles-2025.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-types-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-types-2025.xsd",
      "https://xbrl.sec.gov/country/2025/country-2025.xsd",
      "https://xbrl.sec.gov/dei/2025/dei-2025.xsd",
      "https://xbrl.sec.gov/naics/2025/naics-2025.xsd",
      "https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd"
     ]
    },
    "definitionLink": {
     "local": [
      "xoma-20251121_def.xml"
     ]
    },
    "labelLink": {
     "local": [
      "xoma-20251121_lab.xml"
     ]
    },
    "presentationLink": {
     "local": [
      "xoma-20251121_pre.xml"
     ]
    }
   },
   "keyStandard": 23,
   "keyCustom": 0,
   "axisStandard": 1,
   "axisCustom": 0,
   "memberStandard": 1,
   "memberCustom": 2,
   "hidden": {
    "total": 3,
    "http://xbrl.sec.gov/dei/2025": 3
   },
   "contextCount": 4,
   "entityCount": 1,
   "segmentCount": 3,
   "elementCount": 31,
   "unitCount": 0,
   "baseTaxonomies": {
    "http://xbrl.sec.gov/dei/2025": 29
   },
   "report": {
    "R1": {
     "role": "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation",
     "longName": "100000 - Document - Document and Entity Information",
     "shortName": "Document and Entity Information",
     "isDefault": "true",
     "groupType": "document",
     "subGroupType": "",
     "menuCat": "Cover",
     "order": "1",
     "firstAnchor": {
      "contextRef": "duration_2025-11-21_to_2025-11-21",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "p",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "d65279d8k.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "duration_2025-11-21_to_2025-11-21",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "p",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "d65279d8k.htm",
      "first": true,
      "unique": true
     }
    }
   },
   "tag": {
    "dei_AmendmentFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AmendmentFlag",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Amendment Flag",
        "terseLabel": "Amendment Flag",
        "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission."
       }
      }
     },
     "auth_ref": []
    },
    "dei_CityAreaCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "CityAreaCode",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "City Area Code",
        "terseLabel": "City Area Code",
        "documentation": "Area code of city"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_ClassOfStockDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "ClassOfStockDomain",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Class of Stock [Domain]",
        "terseLabel": "Class of Stock [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_CommonStockMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "CommonStockMember",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Common Stock [Member]",
        "terseLabel": "Common Stock [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_CoverAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "CoverAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Cover [Abstract]",
        "terseLabel": "Cover [Abstract]",
        "documentation": "Cover page."
       }
      }
     },
     "auth_ref": []
    },
    "xoma_DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.xoma.com/20251121",
     "localname": "DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Depositary Shares Each Representing 11000th Interest In A Share Of 8.375 Series B Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]",
        "terseLabel": "Depositary Shares Each Representing 11000th Interest In A Share Of 8.375 Series B Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "xoma_DocumentAndEntityInformationLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.xoma.com/20251121",
     "localname": "DocumentAndEntityInformationLineItems",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Document And Entity Information [Line Items]",
        "terseLabel": "Document And Entity Information [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "xoma_DocumentAndEntityInformationTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.xoma.com/20251121",
     "localname": "DocumentAndEntityInformationTable",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Document And Entity Information [Table]",
        "terseLabel": "Document And Entity Information [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentPeriodEndDate": {
     "xbrltype": "dateItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentPeriodEndDate",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Document Period End Date",
        "terseLabel": "Document Period End Date",
        "documentation": "For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentType": {
     "xbrltype": "submissionTypeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentType",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Document Type",
        "terseLabel": "Document Type",
        "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressAddressLine1": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressAddressLine1",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Address, Address Line One",
        "terseLabel": "Entity Address, Address Line One",
        "documentation": "Address Line 1 such as Attn, Building Name, Street Name"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressAddressLine2": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressAddressLine2",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Address, Address Line Two",
        "terseLabel": "Entity Address, Address Line Two",
        "documentation": "Address Line 2 such as Street or Suite number"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressCityOrTown": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressCityOrTown",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Address, City or Town",
        "terseLabel": "Entity Address, City or Town",
        "documentation": "Name of the City or Town"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressPostalZipCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressPostalZipCode",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Address, Postal Zip Code",
        "terseLabel": "Entity Address, Postal Zip Code",
        "documentation": "Code for the postal or zip code"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressStateOrProvince": {
     "xbrltype": "stateOrProvinceItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressStateOrProvince",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Address, State or Province",
        "terseLabel": "Entity Address, State or Province",
        "documentation": "Name of the state or province."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityCentralIndexKey": {
     "xbrltype": "centralIndexKeyItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityCentralIndexKey",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Central Index Key",
        "terseLabel": "Entity Central Index Key",
        "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityEmergingGrowthCompany": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityEmergingGrowthCompany",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Emerging Growth Company",
        "terseLabel": "Entity Emerging Growth Company",
        "documentation": "Indicate if registrant meets the emerging growth company criteria."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityFileNumber": {
     "xbrltype": "fileNumberItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityFileNumber",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity File Number",
        "terseLabel": "Entity File Number",
        "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityIncorporationStateCountryCode": {
     "xbrltype": "edgarStateCountryItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityIncorporationStateCountryCode",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Incorporation State Country Code",
        "terseLabel": "Entity Incorporation State Country Code",
        "documentation": "Two-character EDGAR code representing the state or country of incorporation."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityRegistrantName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityRegistrantName",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Registrant Name",
        "terseLabel": "Entity Registrant Name",
        "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_EntityTaxIdentificationNumber": {
     "xbrltype": "employerIdItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityTaxIdentificationNumber",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Entity Tax Identification Number",
        "terseLabel": "Entity Tax Identification Number",
        "documentation": "The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS."
       }
      }
     },
     "auth_ref": [
      "r1"
     ]
    },
    "dei_LocalPhoneNumber": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "LocalPhoneNumber",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Local Phone Number",
        "terseLabel": "Local Phone Number",
        "documentation": "Local phone number for entity."
       }
      }
     },
     "auth_ref": []
    },
    "xoma_M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.xoma.com/20251121",
     "localname": "M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "M 8.625 Series A Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]",
        "terseLabel": "M 8.625 Series A Cumulative Perpetual Preferred Stock Par Value 0.05 Per Share [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_PreCommencementIssuerTenderOffer": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "PreCommencementIssuerTenderOffer",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pre Commencement Issuer Tender Offer",
        "terseLabel": "Pre Commencement Issuer Tender Offer",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r3"
     ]
    },
    "dei_PreCommencementTenderOffer": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "PreCommencementTenderOffer",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pre Commencement Tender Offer",
        "terseLabel": "Pre Commencement Tender Offer",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r5"
     ]
    },
    "dei_Security12bTitle": {
     "xbrltype": "securityTitleItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "Security12bTitle",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Security 12b Title",
        "terseLabel": "Security 12b Title",
        "documentation": "Title of a 12(b) registered security."
       }
      }
     },
     "auth_ref": [
      "r0"
     ]
    },
    "dei_SecurityExchangeName": {
     "xbrltype": "edgarExchangeCodeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "SecurityExchangeName",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Security Exchange Name",
        "terseLabel": "Security Exchange Name",
        "documentation": "Name of the Exchange on which a security is registered."
       }
      }
     },
     "auth_ref": [
      "r2"
     ]
    },
    "dei_SolicitingMaterial": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "SolicitingMaterial",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Soliciting Material",
        "terseLabel": "Soliciting Material",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r4"
     ]
    },
    "us-gaap_StatementClassOfStockAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "StatementClassOfStockAxis",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Class of Stock [Axis]",
        "terseLabel": "Class of Stock [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_TradingSymbol": {
     "xbrltype": "tradingSymbolItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "TradingSymbol",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Symbol",
        "terseLabel": "Trading Symbol",
        "documentation": "Trading symbol of an instrument as listed on an exchange."
       }
      }
     },
     "auth_ref": []
    },
    "dei_WrittenCommunications": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "WrittenCommunications",
     "presentation": [
      "http://www.xoma.com//20251121/taxonomy/role/DocumentDocumentAndEntityInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Written Communications",
        "terseLabel": "Written Communications",
        "documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act."
       }
      }
     },
     "auth_ref": [
      "r6"
     ]
    }
   }
  }
 },
 "std_ref": {
  "r0": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b"
  },
  "r1": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b-2"
  },
  "r2": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "d1-1"
  },
  "r3": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "13e",
   "Subsection": "4c"
  },
  "r4": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "14a",
   "Subsection": "12"
  },
  "r5": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "14d",
   "Subsection": "2b"
  },
  "r6": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Securities Act",
   "Number": "230",
   "Section": "425"
  }
 }
}
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>ZIP
<SEQUENCE>15
<FILENAME>0001193125-25-290638-xbrl.zip
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
begin 644 0001193125-25-290638-xbrl.zip
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M>9B#E)6.2A\N9B#_=WQ,>PMB_Y3/*KOCCF^);]=/=N'X.^;YGO\#4$L#!!0
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MK%EO)I:?A]K1_3&.U#+5AX0D24K!0_Z&EE3HNF$J;WVC-Q0,8*& Q1!;-T;
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M+3(P,C4Q,3(Q+GAS9%!+ 0(4 Q0    ( &U =5O>29'2-08  +XX   5
M          "  ?\:  !X;VUA+3(P,C4Q,3(Q7V1E9BYX;6Q02P$"% ,4
M" !M0'5;L2_+1) (  "C8   %0              @ %G(0  >&]M82TR,#(U
M,3$R,5]L86(N>&UL4$L! A0#%     @ ;4!U6WYQ%'SG!0  R3P  !4
M         ( !*BH  'AO;6$M,C R-3$Q,C%?<')E+GAM;%!+!08     !0 %
+ $,!  !$,      !

end
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>XML
<SEQUENCE>16
<FILENAME>d65279d8k_htm.xml
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
<XML>
<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xoma="http://www.xoma.com/20251121">
    <link:schemaRef xlink:href="xoma-20251121.xsd" xlink:type="simple"/>
    <context id="duration_2025-11-21_to_2025-11-21">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000791908</identifier>
        </entity>
        <period>
            <startDate>2025-11-21</startDate>
            <endDate>2025-11-21</endDate>
        </period>
    </context>
    <context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000791908</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">us-gaap:CommonStockMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-11-21</startDate>
            <endDate>2025-11-21</endDate>
        </period>
    </context>
    <context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000791908</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">xoma:M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-11-21</startDate>
            <endDate>2025-11-21</endDate>
        </period>
    </context>
    <context id="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000791908</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">xoma:DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-11-21</startDate>
            <endDate>2025-11-21</endDate>
        </period>
    </context>
    <dei:EntityRegistrantName
      contextRef="duration_2025-11-21_to_2025-11-21"
      id="Hidden_dei_EntityRegistrantName">XOMA Royalty Corp</dei:EntityRegistrantName>
    <dei:AmendmentFlag contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-322">false</dei:AmendmentFlag>
    <dei:EntityCentralIndexKey
      contextRef="duration_2025-11-21_to_2025-11-21"
      id="Hidden_dei_EntityCentralIndexKey">0000791908</dei:EntityCentralIndexKey>
    <dei:DocumentType contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-357">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-358">2025-11-21</dei:DocumentPeriodEndDate>
    <dei:EntityIncorporationStateCountryCode contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-359">NV</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-360">001-39801</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-361">52-2154066</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1 contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-362">2200 Powell Street</dei:EntityAddressAddressLine1>
    <dei:EntityAddressAddressLine2 contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-363">Suite 310</dei:EntityAddressAddressLine2>
    <dei:EntityAddressCityOrTown contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-364">Emeryville</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-365">CA</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-366">94608</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-367">(510)</dei:CityAreaCode>
    <dei:LocalPhoneNumber contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-368">204-7200</dei:LocalPhoneNumber>
    <dei:WrittenCommunications contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-369">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-370">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-371">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-372">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember"
      id="ixv-373">Common Stock, $0.0075 par value</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember"
      id="ixv-374">XOMA</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_us-gaap-CommonStockMember"
      id="ixv-375">NASDAQ</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-376">8.625% Series A Cumulative Perpetual Preferred Stock, par value $0.05 per share</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-377">XOMAP</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-M8.625SeriesACumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-378">NASDAQ</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-379">Depositary Shares (each representing 1/1000th interest in a share of 8.375% Series B Cumulative Perpetual Preferred Stock, par value $0.05 per share)</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-380">XOMAO</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2025-11-21_to_2025-11-21_us-gaap-StatementClassOfStockAxis_xoma-DepositarySharesEachRepresenting11000thInterestInAShareOf8.375SeriesBCumulativePerpetualPreferredStockParValue0.05PerShareMember"
      id="ixv-381">NASDAQ</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany contextRef="duration_2025-11-21_to_2025-11-21" id="ixv-382">false</dei:EntityEmergingGrowthCompany>
</xbrl>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
