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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-06-30</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001339210</issuerCik>
        <issuerName>Mercantile Absolute Return Fund for Tax-Exempt/Deferred Investors (TEDI) LLC</issuerName>
        <issuerTradingSymbol>N/A</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000064908</rptOwnerCik>
            <rptOwnerName>MERCANTILE BANKSHARES CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2 HOPKINS PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Limited Liability Company Interest</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>135000</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Mercantile Absolute Return Fund for Tax Exempt/Deferred Investors (TEDI) LLC (the ?Company?) is a limited liability company organized under the laws of the State of Delaware and registered under the Investment Company Act of 1940, as amended, as a closed-end, non-diversified management investment company.  Each Interest is a percentage of ownership interest in the Company.  The value of each Interest is the corresponding percentage of the net asset value of the Company (as more fully set forth in the Company documents available with the Securities and Exchange Commission (?SEC?)).

Filer?s Interest has been held directly by Mercantile Bankshares Corporation (?MBC?) since June 30, 2006, which was the effective date of the registration statement filed by the Company with the SEC on June 29, 2006 (the ?Registration Statement?).  Filer?s Interest was in exchange for the seed capital that MBC placed into the Company.</footnote>
        <footnote id="F2">Filer?s Interest represented 100% of the outstanding Interests of the Company as of June 30, 2006.  However, as a result of subsequent sales of Interest, Filer?s Interest currently represents less than 100% of the outstanding Interests.  The percentage interest in the Company held by MBC at a given time is related to the investments made by other investors in the Company and is subject to change when other investors buy or sell Interests.  The audited financials attached by reference to the Registration Statement inadvertently state that the seed money Interest was held by and received in exchange for consideration tendered by Mercantile Capital Advisors, Inc., an indirect wholly-owned subsidiary of MBC.  In fact, as noted herein, MBC directly paid for and received the Interest.</footnote>
        <footnote id="F3">The Interest held by MBC represented 100% of the Interests outstanding at the conclusion of the transaction.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mercantile Bankshares Corporation   By:  /s/ John L. Unger, Secretary</signatureName>
        <signatureDate>2006-08-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
