CLAYTON WILLIAMS ENERGY INC /DE

• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND X-A LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND X-C LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND X-B LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND IX-B LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST OIL & GAS INCOME FUND IX-A LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST OIL & GAS INCOME FUND X-B LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST OIL & GAS INCOME FUND X-A LP · on record since Apr 4, 2006
• 10% owner at SOUTHWEST ROYALTIES INC INCOME FUND V · on record since Sep 25, 2006
• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND VII-B L P · on record since Sep 25, 2006
• 10% owner at SOUTHWEST ROYALTIES INC INCOME FUND VI · on record since Sep 25, 2006
• 10% owner at SOUTHWEST OIL & GAS INCOME FUND VIII-A L P · on record since Jul 3, 2006
• 10% owner at SOUTHWEST OIL & GAS INCOME FUND VII A L P · on record since Jul 3, 2006
• 10% owner at SOUTHWEST ROYALTIES INSTITUTIONAL INCOME FUND VIII B L P · on record since Jul 3, 2006