X0303 4 2010-12-29 0 0000003982 Allis Chalmers Energy Inc. ALY 0001425197 Patterson Mark C 5075 WESTHEIMER, SUITE 890 HOUSTON TX 77056 0 1 0 0 Sr Vice Pres - Rental Services Common Stock 2010-12-29 4 F 0 12021 6.76 D 33326 D Common Stock 2010-12-29 4 A 0 75000 6.76 A 108326 D Common Stock 2010-12-29 4 F 0 20724 6.76 D 87602 D Effective December 29, 2010, the Compensation Committee of the Board of Directors of the Issuer approved the acceleration of the vesting of 43,500 shares of restricted stock of which 12,021 of such shares were withheld to satisfy tax obligations in connection with the vesting of such shares. The 43,500 shares of restricted stock includes two grants: 6,000 shares of which 1,659 shares were withheld and 37,500 shares of which 10,362 shares were withheld. Effective December 29, 2010, the Compensation Committee of the Board of Directors of the Issuer approved the acceleration of the vesting of 75,000 shares of performance-based restricted stock. These shares were withheld to satisfy tax obligations in connection with the vesting of 75,000 shares of performance-based restricted stock. The decision to accelerate the vesting of such equity was done to provide certain tax benefits to the Reporting Person and the Issuer. /s/ Theodore F. Pound III through POA 2011-01-03