-----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,
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 mFhggLUc8diMUH3ApVjf2g==

<SEC-DOCUMENT>0001181431-09-028069.txt : 20090601
<SEC-HEADER>0001181431-09-028069.hdr.sgml : 20090601
<ACCEPTANCE-DATETIME>20090601192701
ACCESSION NUMBER:		0001181431-09-028069
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090528
FILED AS OF DATE:		20090601
DATE AS OF CHANGE:		20090601

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:		09866461

	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:			SCULLY JOHN H
		CENTRAL INDEX KEY:			0001202553

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		09866456

	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 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:		09866459

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCDERMOTT EDWARD H
		CENTRAL INDEX KEY:			0001252464

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		09866454

	MAIL ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		STE 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:		09866460

	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:			OBERNDORF WILLIAM E
		CENTRAL INDEX KEY:			0001218663

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		09866455

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

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:			Elizabeth R. & William J. Patterson Foundation
		CENTRAL INDEX KEY:			0001391548
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05667
		FILM NUMBER:		09866457

	BUSINESS ADDRESS:	
		STREET 1:		591 REDWOOD HIGHWAY
		STREET 2:		SUITE 3215
		CITY:			MILL VALLEY
		STATE:			CA
		ZIP:			94941
		BUSINESS PHONE:		415-384-2275

	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:		09866458

	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
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd244315.xml
<DESCRIPTION>STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-05-28</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>0001391548</rptOwnerCik>
            <rptOwnerName>Elizabeth R. &amp; William J. Patterson Foundation</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>591 REDWOOD HIGHWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3215</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>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001252464</rptOwnerCik>
            <rptOwnerName>MCDERMOTT EDWARD 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>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-05-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3800000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.60</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5913400</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 entities and individuals directly selling the shares reported on this form are SPO Partners II, L.P. (&quot;SPO Partners&quot;), which sold 3,749,200 shares, William E. Oberndorf (&quot;WEO&quot;), who sold 42,300 shares and the Elizabeth R. &amp; William J. Patterson Foundation (&quot;WJPFND&quot;), which sold 8,500 shares.</footnote>
        <footnote id="F2">Due to the sales causing this filing, 5,913,400 shares are owned directly by SPO Partners, 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;), WEO, William J. Patterson (&quot;WJP&quot;) and Edward H. McDermott (&quot;EHM&quot;), the four controlling persons of SPO Corp.  These shares are represented in the running total in Column 5 above. Additionally, due to these sales, WEO owns 66,700 shares in his IRA, which is self-directed and WJPFND owns 13,400 shares of the issuer's common stock.</footnote>
        <footnote id="F3">Additionally, (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 &amp; William Ernst Oberndorf.</footnote>
    </footnotes>

    <remarks>The persons listed in the Notes 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>2009-06-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
