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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001169264</issuerCik>
        <issuerName>SYNIVERSE HOLDINGS INC</issuerName>
        <issuerTradingSymbol>SVR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001105021</rptOwnerCik>
            <rptOwnerName>GTCR GOLDER RAUNER LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GTCR GOLDER RAUNER, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>SEARS TOWER #6100</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606-6402</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>See remarks below</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1212</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.57</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4144</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>837</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.36</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3307</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4323025</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Reflects shares received by GTCR Golder Rauner, L.L.C. (&quot;GTCR&quot;) as a result of pro rata distributions from GTCR Co-Invest, L.P. (&quot;Co-Invest&quot;) that were exempt from Section 16 of the Securities Exchange Act of 1934, as amended, pursuant to Rule 16a-13 promulgated thereunder.</footnote>
        <footnote id="F2">Represents the weighted average price of the shares sold.  The prices actually received ranged from (i) $17.24 to $17.80 for sales occurring on August 20, 2008 and (ii) $17.20 to $17.54 for sales occurring on August 21, 2008.  The reporting person will provide to the issuer, any security holder of the issuer or the SEC staff, upon request, information regarding the number of shares sold at each price within the range.</footnote>
        <footnote id="F3">Reflects 4,323,025 shares beneficially owned by GTCR Partners VII, Co-Invest and GTCR Partners VI, L.P. (&quot;GTCR Partners VI&quot;) by virtue of GTCR being the general partner of GTCR Partners VII, Co-Invest and GTCR Partners VI. This aggregate share amount includes shares held directly by GTCR Fund VII, L.P. (&quot;Fund VII&quot;), GTCR Fund VII/A, L.P. (&quot;Fund VII/A&quot;) and GTCR Capital Partners, L.P. (&quot;Capital Partners&quot;), by virtue of: (i) GTCR Partners VII being the general partner of Fund VII and Fund VII/A, (ii) GTCR Mezzanine Partners, L.P. (&quot;Mezzanine Partners&quot;) being the general partner of Capital Partners and (iii) GTCR Partners VI being the general partner of Mezzanine Partners.(Continued to Footnote 4)</footnote>
        <footnote id="F4">As such, GTCR may be deemed to be the beneficial owner of such shares. GTCR expressly disclaims beneficial ownership of such shares except to the extent of its pecuniary interest therein. The filing of this form shall not be deemed an admission that GTCR is, for Section 16 purposes or otherwise, the beneficial owner of such shares, except to the extent of its pecuniary interest therein.</footnote>
    </footnotes>

    <remarks>The Reporting Person may be deemed a director by virtue of its members serving on the board of directors of Syniverse Holdings, Inc.</remarks>

    <ownerSignature>
        <signatureName>/s/ Jody S. Gale under a Power of Attorney</signatureName>
        <signatureDate>2008-08-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
