<SEC-DOCUMENT>0000935836-25-000309.txt : 20250506
<SEC-HEADER>0000935836-25-000309.hdr.sgml : 20250506
<ACCEPTANCE-DATETIME>20250506190605
ACCESSION NUMBER:		0000935836-25-000309
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250502
FILED AS OF DATE:		20250506
DATE AS OF CHANGE:		20250506

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			EcoR1 Capital, LLC
		CENTRAL INDEX KEY:			0001587114
		ORGANIZATION NAME:           	
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-35676
		FILM NUMBER:		25918800

	BUSINESS ADDRESS:	
		STREET 1:		357 TEHAMA STREET #3
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94103
		BUSINESS PHONE:		415-448-6534

	MAIL ADDRESS:	
		STREET 1:		357 TEHAMA STREET #3
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94103

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PROTHENA CORP PUBLIC LTD CO
		CENTRAL INDEX KEY:			0001559053
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				000000000
		STATE OF INCORPORATION:			L2
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		77 SIR JOHN ROGERSON'S QUAY, BLOCK C
		STREET 2:		GRAND CANAL DOCKLANDS
		CITY:			DUBLIN 2
		STATE:			L2
		ZIP:			D02 VK60
		BUSINESS PHONE:		011-353-1-236-2500

	MAIL ADDRESS:	
		STREET 1:		77 SIR JOHN ROGERSON'S QUAY, BLOCK C
		STREET 2:		GRAND CANAL DOCKLANDS
		CITY:			DUBLIN 2
		STATE:			L2
		ZIP:			D02 VK60

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Prothena Corp plc
		DATE OF NAME CHANGE:	20121102

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Neotope Corp Ltd
		DATE OF NAME CHANGE:	20120926
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ownership.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-05-02</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001559053</issuerCik>
        <issuerName>PROTHENA CORP PUBLIC LTD CO</issuerName>
        <issuerTradingSymbol>PRTA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001587114</rptOwnerCik>
            <rptOwnerName>EcoR1 Capital, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>357 TEHAMA STREET #3</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94103</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-02</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3317938</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.3621</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8266342</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-05</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>977693</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.1111</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7288649</value>
                    <footnoteId id="F7"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1984053</value>
                    <footnoteId id="F8"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.6433</value>
                    <footnoteId id="F9"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5304596</value>
                    <footnoteId id="F10"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The reporting persons are EcoR1 Capital, LLC (&quot;Ecor1&quot;), Oleg Nodelman and EcoR1 Capital Fund Qualified, L.P. (&quot;Qualified Fund&quot;). EcoR1 is the general partner and investment adviser of private funds, including Qualified Fund (the &quot;Fund&quot;). Mr. Nodelman is the manager and controlling owner of EcoR1. EcoR1 is filing this Form 4 for itself, Mr. Nodelman and Qualified Fund. The filers are filing this Form 4 jointly, but not as a group, and each expressly disclaims membership in a group within the meaning of Rule 13d-5(b) under the Securities Exchange Act of 1934. The Funds hold these securities directly for the benefit of their investors. EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to the Funds. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1. The filers disclaim beneficial ownership of the securities except to the extent of their respective pecuniary interests therein.</footnote>
        <footnote id="F2">Qualified Fund sold 3,097,619 of the shares sold in this transaction.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.2715 to $9.1789, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission upon request, full information regarding the number of shares sold at each seperate price within the ranges set forth in this footnote and footnotes 6 and 9.</footnote>
        <footnote id="F4">After this transaction, Qualified Fund held 7,750,234 shares of the Issuer's Common Stock.</footnote>
        <footnote id="F5">Qualified Fund sold 916,492 of the shares of sold in this transaction.</footnote>
        <footnote id="F6">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $8.1097 to $8.1972, inclusive.</footnote>
        <footnote id="F7">After this transaction, Qualified Fund held 6,833,742 shares of the Issuer's Common Stock</footnote>
        <footnote id="F8">Qualified Fund sold 1,859,851 of the shares sold in this transaction.</footnote>
        <footnote id="F9">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.4637 to $8.5939, inclusive.</footnote>
        <footnote id="F10">After this transaction, Qualified Fund held 4,973,891 of the Issuer's Ordinary Shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Oleg Nodelman</signatureName>
        <signatureDate>2025-05-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
