<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-01-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0002014982</issuerCik>
        <issuerName>SIM Acquisition Corp. I</issuerName>
        <issuerTradingSymbol>SIMA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002026210</rptOwnerCik>
            <rptOwnerName>SIM Sponsor 1 LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DOMINARI HOLDINGS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>725 FIFTH AVE, 23RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002089554</rptOwnerCik>
            <rptOwnerName>Newman Eric</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O DOMINARI HOLDINGS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>725 FIFTH AVE, 23RD FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</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>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Ordinary Shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-01-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Ordinary Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7526669</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Class B ordinary shares will automatically convert into Class A ordinary shares at the time of the Issuer's initial business combination, or at any time prior to the Issuer's initial business combination, at the option of the holder, on a one-for-one basis, subject to certain adjustments. The Class B ordinary shares have no expiration date.</footnote>
        <footnote id="F2">On January 28, 2026, certain accredited investors acquired all of the membership interests in SIM Sponsor 1 LLC (the &quot;Sponsor&quot;) and all of the membership interests of Conroy Partners LLC, the managing member of the Sponsor. This form is being filed to reflect the new manager of Conroy Partners LLC. Eric Newman is the manager of Conroy Partners LLC and holds voting and investment discretion with respect to the ordinary shares held of record by the Sponsor. As such, Mr. Newman may be deemed to have beneficial ownership of the securities held of record by the Sponsor. Mr. Newman disclaims any beneficial ownership of the securities held of record by the Sponsor except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Eric Newman, Manager of Conroy Partners LLC, the Managing Member of SIM Sponsor 1 LLC</signatureName>
        <signatureDate>2026-02-19</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Eric Newman</signatureName>
        <signatureDate>2026-02-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
