<SEC-DOCUMENT>0001179110-21-009703.txt : 20211029
<SEC-HEADER>0001179110-21-009703.hdr.sgml : 20211029
<ACCEPTANCE-DATETIME>20211029152242
ACCESSION NUMBER:		0001179110-21-009703
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210824
FILED AS OF DATE:		20211029
DATE AS OF CHANGE:		20211029

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARCH CAPITAL GROUP LTD.
		CENTRAL INDEX KEY:			0000947484
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21484
		FILM NUMBER:		211362864

	BUSINESS ADDRESS:	
		STREET 1:		WATERLOO HOUSE, GROUND FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM 08
		BUSINESS PHONE:		441-278-9250

	MAIL ADDRESS:	
		STREET 1:		WATERLOO HOUSE, GROUND FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM 08

	FORMER NAME:	
		FORMER CONFORMED NAME:	ARCH CAPITAL GROUP LTD
		DATE OF NAME CHANGE:	20000508

	FORMER NAME:	
		FORMER CONFORMED NAME:	RISK CAPITAL HOLDINGS INC
		DATE OF NAME CHANGE:	19950816

	FORMER NAME:	
		FORMER CONFORMED NAME:	RISK CAPITAL RE INC
		DATE OF NAME CHANGE:	19950703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARCH REINSURANCE LTD.
		CENTRAL INDEX KEY:			0001765678
		STATE OF INCORPORATION:			D0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	811-21484
		FILM NUMBER:		211362863

	BUSINESS ADDRESS:	
		STREET 1:		WATERLOO HOUSE, FIRST FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM08
		BUSINESS PHONE:		4412789200

	MAIL ADDRESS:	
		STREET 1:		WATERLOO HOUSE, FIRST FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM08

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CALAMOS STRATEGIC TOTAL RETURN FUND
		CENTRAL INDEX KEY:			0001275214
		IRS NUMBER:				043785941
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		2020 CALAMOS COURT
		STREET 2:		C/O CALAMOS ADVISORS LLC
		CITY:			NAPERVILLE
		STATE:			IL
		ZIP:			60653
		BUSINESS PHONE:		6302451046

	MAIL ADDRESS:	
		STREET 1:		2020 CALAMOS COURT
		STREET 2:		C/O CALAMOS ADVISORS LLC
		CITY:			NAPERVILLE
		STATE:			IL
		ZIP:			60653
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 3 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-08-24</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001275214</issuerCik>
        <issuerName>CALAMOS STRATEGIC TOTAL RETURN FUND</issuerName>
        <issuerTradingSymbol>CSQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000947484</rptOwnerCik>
            <rptOwnerName>ARCH CAPITAL GROUP LTD.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 PITTS BAY ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>WATERLOO HOUSE, GROUND FLOOR</rptOwnerStreet2>
            <rptOwnerCity>PEMBROKE</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>HM 08</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001765678</rptOwnerCik>
            <rptOwnerName>ARCH REINSURANCE LTD.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 PITTS BAY ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>WATERLOO HOUSE, 1ST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>PEMBROKE</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>HM 08</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Series D Mandatory Redeemable Preferred Shares</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>280000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote 1</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The reported securities are owned directly by Arch Reinsurance Ltd., a wholly-owned subsidiary of Arch Capital Group Ltd.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Francois Morin</signatureName>
        <signatureDate>2021-10-29</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Tim Peckett</signatureName>
        <signatureDate>2021-10-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
