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SEC EDGAR · Insider purchase

TSM: SPLINTER MICHAEL R reported buying shares

1 reported purchase of non-derivative securities. Code P includes open-market and private purchases; it does not establish motive.

Follow TSM
Became public
Nov 9, 2026, 6:15 AM EST
Event / period date
Nov 5, 2026
Collected
Nov 9, 2026, 6:16 AM EST

Why this is connected

This filing identifies TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD as the issuer of the security. The company's SEC identifier connects it to TSM.

Open the original source ↗Follow company activity in TSM

Reported transactions

SPLINTER MICHAEL R (Director)

840 shares · American Depositary Shares (TSM)

Nov 5, 2026 · $357.00 per share

Value calculated from the reported shares and prices: $299,880.00.

Code P covers open-market and private purchases. Grants, option exercises, and tax withholding are excluded from purchase results. Read the source footnotes for ownership and pricing details.

Source evidence

Read the source excerpt or record
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-11-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001046179</issuerCik>
        <issuerName>TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD</issuerName>
        <issuerTradingSymbol>TSM</issuerTradingSymbol>
        <issuerForeignTradingSymbol>2330.TW</issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001188935</rptOwnerCik>
            <rptOwnerName>SPLINTER MICHAEL R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>NO. 8, LI-HSIN ROAD 6</rptOwnerStreet1>
            <rptOwnerStreet2>HSINCHU SCIENCE PARK</rptOwnerStreet2>
            <rptOwnerCity>HSINCHU</rptOwnerCity>
            <rptOwnerNonUSStateTerritory>TAIWAN</rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>F5</rptOwnerCountry>
            <rptOwnerZipCode>300096</rptOwnerZipCode>
            <rptOwnerStateDescription>TAIWAN</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-11-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>840</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>357</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8405</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>795</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse's IRA</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Each American Depositary Share represents five (5) Common Shares.</footnote>
        <footnote id="F2">The shares reported are owned by the Kylie Souria Fenske Irrevocable Trust, for which the reporting person serves as trustee and exercises investing authority over such shares.</footnote>
        <footnote id="F3">The shares reported are owned by the Cole David Fenske Irrevocable Trust, for which the reporting person serves as trustee and exercises investing authority over such shares.</footnote>
        <footnote id="F4">The shares reported are owned by the Avery Michael Splinter Irrevocable Trust, for which the reporting person serves as trustee and exercises investing authority over such shares</footnote>
        <footnote id="F5">The shares reported are owned by the Samantha Lilia Roboostoff Irrevocable Trust, for which the reporting person serves as trustee and exercises investing authority over such shares.</footnote>
        <footnote id="F6">The shares reported are owned by the Cash Fenske Irrevocable Trust, for which the reporting person serves as trustee and exercises investing authority over such shares.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jen-Chau Huang, as attorney-in-fact</signatureName>
        <signatureDate>2026-11-09</signatureDate>
    </ownerSignature>
</ownershipDocument>

Price change after we could observe it

+4.25% TSM

Adjusted closing prices from Nov 10, 2026 to Nov 11, 2026. SPY changed 1.32% over the same dates. The start is the first available close after both publication and collection. This is a price comparison, not an executed trade, investor profit, or a backtested strategy.

Congressional trading in TSM

These disclosures provide context. Their presence does not establish a link between a trader and the event.

Original documents control. Public records can be amended, and company connections may require interpretation. Nothing here is investment advice.