-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 E+w13VTfGYdkHMLR6n+UuoPeb3qapYz/3mlIFxJscJ4vdko2p8VPayc6q4lHQR7O
 urxnDQGK4uDL6uGTxprEvg==

<SEC-DOCUMENT>0001181431-06-039693.txt : 20060703
<SEC-HEADER>0001181431-06-039693.hdr.sgml : 20060703
<ACCEPTANCE-DATETIME>20060703133232
ACCESSION NUMBER:		0001181431-06-039693
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060629
FILED AS OF DATE:		20060703
DATE AS OF CHANGE:		20060703

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CABOT CORP
		CENTRAL INDEX KEY:			0000016040
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS CHEMICAL PRODUCTS [2890]
		IRS NUMBER:				042271897
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		TWO SEAPORT LANE SUITE 1300
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02109-1806
		BUSINESS PHONE:		6173450100

	MAIL ADDRESS:	
		STREET 1:		TWO SEAPORT LANE SUITE 1300
		CITY:			BOSTON
		STATE:			MA
		ZIP:			82109

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CABOT GODFREY L INC
		DATE OF NAME CHANGE:	19680418

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OBERNDORF WILLIAM E
		CENTRAL INDEX KEY:			0001218663

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940285

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		4153836600

	MAIL ADDRESS:	
		STREET 1:		SPO PARTNERS & CO
		STREET 2:		591 REDWOOD HWY STE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCULLY JOHN H
		CENTRAL INDEX KEY:			0001202553

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940286

	MAIL ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		SUITE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SPO PARTNERS II LP
		CENTRAL INDEX KEY:			0001046206
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940287

	BUSINESS ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY STE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941
		BUSINESS PHONE:		4153836600

	MAIL ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY, 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941

	FORMER NAME:	
		FORMER CONFORMED NAME:	MAIN STREET PARTNERS LP
		DATE OF NAME CHANGE:	19970916

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PATTERSON WILLIAM J
		CENTRAL INDEX KEY:			0001202551

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940288

	MAIL ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		SUITE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SPO ADVISORY CORP
		CENTRAL INDEX KEY:			0000919468
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940289

	BUSINESS ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		SUITE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941
		BUSINESS PHONE:		4153836600

	FORMER NAME:	
		FORMER CONFORMED NAME:	SF ADVISORY CORP
		DATE OF NAME CHANGE:	19990329

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SPO ADVISORY PARTNERS LP
		CENTRAL INDEX KEY:			0001252456
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		06940290

	MAIL ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		STE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd122968.xml
<DESCRIPTION>STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-06-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000016040</issuerCik>
        <issuerName>CABOT CORP</issuerName>
        <issuerTradingSymbol>CBT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000919468</rptOwnerCik>
            <rptOwnerName>SPO ADVISORY CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY, SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001252456</rptOwnerCik>
            <rptOwnerName>SPO ADVISORY PARTNERS LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY, SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001046206</rptOwnerCik>
            <rptOwnerName>SPO PARTNERS II LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY, SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202553</rptOwnerCik>
            <rptOwnerName>SCULLY JOHN H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY,  SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001218663</rptOwnerCik>
            <rptOwnerName>OBERNDORF WILLIAM E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY, SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202551</rptOwnerCik>
            <rptOwnerName>PATTERSON WILLIAM J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY, SUITE 3215</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MILL VALLEY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94941</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-06-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.60</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9110350</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-06-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.50</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9110450</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The entity acquiring these shares is SPO Partners, II, L.P.  As a result of the purchases causing this filing, 8,352,400 shares of the issuer's common stock are owned directly by SPO Partners II, L.P. (&quot;SPO Partners&quot;), and may be deemed to be indirectly beneficially owned by (i) SPO Advisory Partners, L.P. (&quot;SPO Advisory&quot;), the sole general partner of SPO Partners, (ii) SPO Advisory Corp. (&quot;SPO Corp.&quot;), the sole general partner of SPO Advisory, and (iii) John H. Scully (&quot;JHS&quot;), William E. Oberndorf (&quot;WEO&quot;) and William J. Patterson (&quot;WJP&quot;), the three controlling persons of SPO Corp.  309,400 shares of the issuer's common stock are owned directly by San Francisco Partners II, L.P. (&quot;SF Partners&quot;), and may be deemed to be indirectly beneficially owned by (i) SF Advisory Partners, L.P. (&quot;SF Advisory&quot;), the sole general partner of SF Partners, (ii) SPO Corp., the sole general partner of SF Advisory, and (iii)
 JHS, WEO and WJP, the three controlling persons of SPO Corp.</footnote>
        <footnote id="F2">Additionally, separate from the entities above, (i) 333,650 shares of the issuer's common stock may be deemed to be indirectly beneficially owned by WEO, solely in his capacity as a trustee for the William and Susan Oberndorf Trust, dated 10/15/98 (&quot;Oberndorf Trust&quot;), (ii) 100,000 shares may be deemed to be indirectly beneficially owned by WEO solely in his capacity as general partner of Oberndorf Family Partners, a California limited partnership and (iii) 10,000 shares may be deemed to be indirectly beneficially owned by WEO solely in his capacity as trustee for the accounts of his two children, Peter C. Oberndorf and William Ernst Oberndorf.</footnote>
        <footnote id="F3">Additionally, 5,000 shares of the issuer's common stock are owned directly by Betty Jane Weimer.</footnote>
    </footnotes>

    <remarks>The persons listed in Note (1) above ( each a &quot;Reporting Person&quot; ) may be deemed to form a &quot;group&quot;, as such term is defined in Rule 13d-5(b)(1) promulgated under the Securities Exchange Act of 1934, for purposes of this filing.  This filing shall not be deemed as an admission by any Reporting Person that such person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement.  Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of such person's pecuniary interest, if any, therein.</remarks>

    <ownerSignature>
        <signatureName>Kim M. Silva, Attorney-in-Fact</signatureName>
        <signatureDate>2006-07-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
