-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 SABLtT+uyEXukowDftE58D3+nMZdFwHj9SPdPRTNwOcgBQSgo0e7hkbfy42J+UUM
 waQsFg6ZQ/db8iUNnGtsOA==

<SEC-DOCUMENT>0001179110-06-010033.txt : 20060504
<SEC-HEADER>0001179110-06-010033.hdr.sgml : 20060504
<ACCEPTANCE-DATETIME>20060504190451
ACCESSION NUMBER:		0001179110-06-010033
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060503
FILED AS OF DATE:		20060504
DATE AS OF CHANGE:		20060504

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SEABRIGHT INSURANCE HOLDINGS INC
		CENTRAL INDEX KEY:			0001267201
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				000000000

	BUSINESS ADDRESS:	
		STREET 1:		2101 4TH AVENUE
		STREET 2:		SUITE 1600
		CITY:			SEATTLE
		STATE:			WA
		ZIP:			98121
		BUSINESS PHONE:		2067708300

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SUMMIT PARTNERS V LP
		CENTRAL INDEX KEY:			0001258823
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51124
		FILM NUMBER:		06809989

	BUSINESS ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6178241000

	MAIL ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SUMMIT PARTNERS LLC
		CENTRAL INDEX KEY:			0001258824
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51124
		FILM NUMBER:		06809990

	BUSINESS ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6178241000

	MAIL ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SUMMIT PARTNERS VI GP LP
		CENTRAL INDEX KEY:			0001258826
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51124
		FILM NUMBER:		06809991

	BUSINESS ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6178241000

	MAIL ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SUMMIT PARTNERS VI GP LLC
		CENTRAL INDEX KEY:			0001258825
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51124
		FILM NUMBER:		06809992

	BUSINESS ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6178241000

	MAIL ADDRESS:	
		STREET 1:		SUMMIT PARTNERS
		STREET 2:		222 BERKELEY ST 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SUMMIT PARTNERS L P
		CENTRAL INDEX KEY:			0000830588
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51124
		FILM NUMBER:		06809993

	BUSINESS ADDRESS:	
		STREET 1:		C/O SUMMIT PARTNERS
		STREET 2:		600 ATLANTIC AVE
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210
		BUSINESS PHONE:		6178241000

	MAIL ADDRESS:	
		STREET 1:		C/O SUMMIT PARTNERS
		STREET 2:		222 BERKELEY STREET 18TH
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-05-03</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001267201</issuerCik>
        <issuerName>SEABRIGHT INSURANCE HOLDINGS INC</issuerName>
        <issuerTradingSymbol>SEAB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000830588</rptOwnerCik>
            <rptOwnerName>SUMMIT PARTNERS L P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258825</rptOwnerCik>
            <rptOwnerName>SUMMIT PARTNERS VI GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258826</rptOwnerCik>
            <rptOwnerName>SUMMIT PARTNERS VI GP LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258824</rptOwnerCik>
            <rptOwnerName>SUMMIT PARTNERS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Former Indirect GP of 10% Ownr</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258823</rptOwnerCik>
            <rptOwnerName>SUMMIT PARTNERS V LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET</rptOwnerStreet1>
            <rptOwnerStreet2>18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Former Indirect GP of 10% Ownr</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3095627</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Manager of GP of Direct Owners</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>182499</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>182499</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>182499</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F5"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Distribution to partners.</footnote>
        <footnote id="F2">Shares of Common Stock are held in the name of Summit Ventures V, L.P.; Summit V Companion Fund, L.P.; Summit V Advisors Fund, L.P.; Summit V Advisors Fund (QP), L.P.; Summit Ventures VI-A, L.P.; Summit Ventures VI-B, L.P.; Summit VI Advisors Fund, L.P.; Summit VI Entrepreneurs Fund, L.P.; and Summit Investors VI, L.P.</footnote>
        <footnote id="F3">Not applicable.</footnote>
        <footnote id="F4">Such shares acquired directly by Summit Partners, L.P.</footnote>
        <footnote id="F5">Such shares distributed by Summit Partners, L.P.</footnote>
    </footnotes>

    <remarks>Summit Partners, L.P. is the manager of Summit Partners VI (GP), LLC, which is the general partner of Summit Partners VI (GP), L.P., which is the general partner of each of Summit Ventures VI-A, L.P., Summit Ventures VI-B, L.P., Summit VI Advisors Fund, L.P., Summit VI Entrepreneurs Fund, L.P. and Summit Investors VI, L.P. Summit Partners, L.P. is the manager of Summit Partners, LLC, which is the general partner of Summit Partners V, L.P., which is the general partner of each of Summit Ventures V, L.P., Summit V Companion Fund, L.P., Summit V Advisors Fund, L.P., and Summit V Advisors Fund (QP), L.P. Summit Partners, L.P. has voting and dispositive authority over the shares held by each of these entities and, therefore, may beneficially own such shares. Each of Summit Partners, L.P., Summit Partners VI (GP), LLC, Summit Partners VI (GP), L.P., Summit Partners, LLC, Summit Partners V, L.P. and Summit Master Company, LLC, which is the general partner of Summit Partners, L.P., disclaims beneficial 
ownership of such shares, except to the extent of its pecuniary interest.Summit Partners, LLC and Summit Partners V, L.P. are no longer subject to Section 16.</remarks>

    <ownerSignature>
        <signatureName>Summit Partners, L.P., by Summit Master Company, LLC, Its General Partner, by Robin W. Devereux, Power of Attorney for Walter G. Kortschak, Member</signatureName>
        <signatureDate>2006-05-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners VI (GP), LLC, by Summit Partners, L.P., its General Partner, by Summit Master Company, LLC, its General Partner, by Robin W. Devereux, Power of Attorney for Walter G. Kortschak, Member</signatureName>
        <signatureDate>2006-05-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners VI (GP), L.P., by Summit Partners VI (GP), LLC, its General Partner, by Summit Partners L.P., its General Partner, by Summit Master Company, LLC, its General Partner, by Robin W. Devereux, Power of Attorney for Walter G. Kortschak, Member</signatureName>
        <signatureDate>2006-05-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners, LLC, by Robin W. Devereux, Power of Attorney for Martin J. Mannion, Member</signatureName>
        <signatureDate>2006-05-04</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Summit Partners V, L.P. by Summit Partners, LLC, Its General Partner, by Robin W. Devereux, Power of Attorney for Martin J. Mannion, Member</signatureName>
        <signatureDate>2006-05-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----