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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2020-08-05</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001614806</issuerCik>
        <issuerName>Great Ajax Corp.</issuerName>
        <issuerTradingSymbol>AJX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001352851</rptOwnerCik>
            <rptOwnerName>Magnetar Financial LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE, 13TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001353085</rptOwnerCik>
            <rptOwnerName>Magnetar Capital Partners LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE, 13TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001368026</rptOwnerCik>
            <rptOwnerName>Supernova Management LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE, 13TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001368027</rptOwnerCik>
            <rptOwnerName>Litowitz Alec N</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1603 ORRINGTON AVENUE, 13TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>EVANSTON</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series A Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.01 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1493750</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series A Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.01 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>465500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.01 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3506250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F7"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.01 per share</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>109500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Series A Warrants and Series B Warrants (collectively the &quot;Warrants&quot;) became exercisable into shares of Common Stock, par value $0.01 per share (&quot;Shares&quot;), of Great Ajax Corp. (the &quot;Issuer&quot;) at an exercise price per share of $10.00 on August 5, 2020.</footnote>
        <footnote id="F2">Represents (a)(i) 1,025,000 Series A Warrants and (ii) 2,975,000 Series B Warrants issued by the Issuer on April 6, 2020, and (b)(i) 468,750 Series A Warrants and (ii) 531,250 Series B Warrants issued by the Issuer on June 3, 2020.  The aforementioned Warrants may be exercised, if at all, on or before 5:00 p.m., Eastern Time on April 6, 2025 (subject to earlier termination as set forth in the applicable Warrant).</footnote>
        <footnote id="F3">Magnetar Financial LLC (&quot;MFL&quot;) serves as investment manager of each of Magnetar Constellation Fund V Ltd, Magnetar Constellation Master Fund, Ltd, Magnetar Longhorn Fund LP, Magnetar SC Fund Ltd and Magnetar Xing He Master Fund Ltd, which are Cayman Islands exempted companies, except for Longhorn Fund, which is a Delaware limited partnership. MFL is the manager of each of Magnetar Constellation Fund V LLC, Purpose Alternative Credit Fund - F LLC and Purpose Alternative Credit Fund - T LLC, which are Delaware limited liability companies.</footnote>
        <footnote id="F4">MFL is the general partner of Magnetar Structured Credit Fund, LP, a Delaware limited partnership (together with all of the foregoing funds, the &quot;Magnetar Funds&quot;). In such capacities, MFL exercises voting and investment power over the Warrants held for the accounts of the Magnetar Funds. MFL is a registered investment adviser under Section 203 of the Investment Advisers Act of 1940, as amended. Magnetar Capital Partners LP (&quot;MCP&quot;), a Delaware limited partnership, is the sole member and parent holding company of MFL. Supernova Management LLC (&quot;Supernova&quot;), a Delaware limited liability company, is the sole general partner of MCP.</footnote>
        <footnote id="F5">The manager of Supernova is Alec N. Litowitz, a citizen of the United States of America.</footnote>
        <footnote id="F6">Each of the Magnetar Funds, MFL, MCP, Supernova and Alec N. Litowitz disclaim beneficial ownership of these Shares except to the extent of their pecuniary interest in the Warrants and the Shares issuable upon exercise of such Warrants.</footnote>
        <footnote id="F7">Represents (a) 465,500 Series A Warrants and (b) 109,500 Series B Warrants issued by the Issuer on May 7, 2020, which may be exercised, if at all, on or before 5:00 p.m., Eastern Time on May 7, 2025 (subject to earlier termination as set forth in the applicable Warrant).</footnote>
    </footnotes>

    <remarks>Exhibit 99.1 - Joint Filing Agreement</remarks>

    <ownerSignature>
        <signatureName>/s/ Alec N. Litowitz, as Manager of Supernova Management LLC, as General Partner of Magnetar Capital Partners LP, as Sole Member of Magnetar Financial LLC</signatureName>
        <signatureDate>2020-08-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Alec N. Litowitz, as Manager of Supernova Management LLC, as General Partner of Magnetar Capital Partners LP</signatureName>
        <signatureDate>2020-08-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Alec N. Litowitz, as Manager of Supernova Management LLC</signatureName>
        <signatureDate>2020-08-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Alec N. Litowitz</signatureName>
        <signatureDate>2020-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
