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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-04</periodOfReport>

    <issuer>
        <issuerCik>0001591956</issuerCik>
        <issuerName>Sphere 3D Corp.</issuerName>
        <issuerTradingSymbol>ANY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002102312</rptOwnerCik>
            <rptOwnerName>Reppas Tiah Norton</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FIRST EXECUTIVE SUITES, 100 E SAN MARCOS</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>SAN MARCOS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92069</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit (RSU)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-03-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2027-03-04</value>
            </exerciseDate>
            <expirationDate>
                <value>2027-03-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>106250</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each RSU represents a contingent right to receive one share of Sphere 3D Corp. common stock.</footnote>
        <footnote id="F2">In addition to the 3/4/2026 RSU, the RSUs reported under Column 9 also include two additional awards. The underlying outstanding shares and vesting schedules are as follows: (i) 6,250 shares outstanding of which 1,250 shares vested on March 1, 2026 and the remaining shares vest quarterly until March 1, 2027; and (ii) 50,000 outstanding shares of which 15,000 shares vested on March 1, 2026 and the remaining shares vest quarterly until 12/1/2027.  These RSUs have been adjusted to reflect the issuer's 1 for 10 reverse stock split effective February 9, 2026.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Denise Garrett For: Tiah Reppas</signatureName>
        <signatureDate>2026-03-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
