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SEC EDGAR · Insider purchase

TSM: Tien Bor-Zen reported employee-plan purchases

3 reported purchases of non-derivative securities. The footnotes identify an employee stock purchase plan; this is not a discretionary-buy signal. Code P includes open-market and private purchases; it does not establish motive.

Became public
Jul 30, 2026, 6:24 AM EDT
Event / period date
Jul 28, 2026
Collected
Nov 6, 2026, 12:58 PM 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 ↗All Congress trades in TSM

Reported transactions

Tien Bor-Zen (VP)

10 shares · American Depositary Shares (TSM)

Jul 28, 2026 · $390.00 per share

5 shares · American Depositary Shares (TSM)

Jul 28, 2026 · $390.00 per share

1,000 shares · Common Shares (2330.TW)

Jul 28, 2026 · $67.97 per share

Value calculated from the reported shares and prices: $73,820.00.

The footnotes identify an employee stock purchase plan. This is not a discretionary-buy signal. 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>2026-07-28</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>0002114023</rptOwnerCik>
            <rptOwnerName>Tien Bor-Zen</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>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares (2330.TW)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13051</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-07-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>390</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>127</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>American Depositary Shares (TSM)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-07-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>390</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>132</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares (2330.TW)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>228</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ESPP Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares (2330.TW)</value>
            </securityTitle>
            <transactionDate>
                <value>2026-07-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>67.97</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares (2330.TW)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>73</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Immediate Family Member</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Each American Depositary Share represents five (5) Common Shares.</footnote>
        <footnote id="F2">Common Shares purchased and held under the issuer's Employee Stock Purchase Plan (&quot;ESPP&quot;).</footnote>
        <footnote id="F3">The price was translated from New Taiwan dollars, NT$2,200, at the rate of NT$32.366 to US$1.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jen-Chau Huang, as attorney-in-fact</signatureName>
        <signatureDate>2026-07-30</signatureDate>
    </ownerSignature>
</ownershipDocument>

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.