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

    <schemaVersion>X0607</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2026-08-06</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0002123955</issuerCik>
        <issuerName>Pinnacle Acquisition Corp</issuerName>
        <issuerTradingSymbol>PNAQ</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002145639</rptOwnerCik>
            <rptOwnerName>Stoyan Paul J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>true</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O PINNACLE ACQUISITION CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>375 SOUTH COUNTY ROAD, SUITE 220</rptOwnerStreet2>
            <rptOwnerCity>PALM BEACH</rptOwnerCity>
            <rptOwnerNonUSStateTerritory></rptOwnerNonUSStateTerritory>
            <rptOwnerCountry>A6</rptOwnerCountry>
            <rptOwnerZipCode>33480</rptOwnerZipCode>
            <rptOwnerStateDescription>ONTARIO, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <remarks>The Reporting Person has an indirect pecuniary interest in the Class B ordinary shares of the Issuer through the Reporting Person's interest in PAC Sponsor, LLC, over which the Reporting Person does not have voting or dispositive control.</remarks>

    <ownerSignature>
        <signatureName>/s/ Paul Stoyan</signatureName>
        <signatureDate>2026-08-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
