X0303 4 2010-08-03 0 0000060849 LUFKIN INDUSTRIES INC LUFK 0001185412 PEREZ PAUL G P.O. BOX 849 LUFKIN TX 75902 0 1 0 0 VP/Gen. Counsel/Secretary COMMON STOCK 2010-08-03 4 M 0 6900 9.25 A 14900 D COMMON STOCK 2010-08-03 4 S 0 6900 43.00 D 8000 D COMMON STOCK 2010-08-03 4 M 0 7500 23.35 A 15500 D COMMON STOCK 2010-08-03 4 S 0 7500 43.00 D 8000 D COMMON STOCK 2010-08-03 4 M 0 430 30.17 A 8430 D COMMON STOCK 2010-08-03 4 S 0 430 43 D 8000 D COMMON STOCK 2010-08-04 4 M 0 7070 30.17 A 15070 D COMMON STOCK 2010-08-04 4 S 0 3230 43 D 11840.00 D COMMON STOCK 2010-08-04 4 S 0 340 43.02 D 11500 D COMMON STOCK 2010-08-04 4 S 0 400 43.03 D 11100 D COMMON STOCK 2010-08-04 4 S 0 1000 43.04 D 10100 D COMMON STOCK 2010-08-04 4 S 0 100 43.06 D 10000 D COMMON STOCK 2010-08-04 4 S 0 2000 43.10 D 8000 D COMMON STOCK 2010-08-04 4 M 0 8750 29.22 A 16750 D COMMON STOCK 2010-08-04 4 S 0 5479 43 D 11271 D COMMON STOCK 2010-08-04 4 S 0 660 43.02 D 10611 D COMMON STOCK 2010-08-04 4 S 0 100 43.03 D 10511 D COMMON STOCK 2010-08-04 4 S 0 900 43.06 D 9611 D COMMON STOCK 2010-08-04 4 S 0 511 43.10 D 9100 D COMMON STOCK 2010-08-04 4 S 0 100 43.11 D 9000 D COMMON STOCK 2010-08-04 4 S 0 500 43.18 D 8500 D COMMON STOCK 2010-08-04 4 S 0 500 43.27 D 8000 D COMMON STOCK 2010-08-04 4 M 0 4000 27.635 A 12000 D COMMON STOCK 2010-08-04 4 S 0 1791 43 D 10209 D COMMON STOCK 2010-08-04 4 S 0 1709 43.0197 D 8500 D COMMON STOCK 2010-08-04 4 S 0 300 43.03 D 8200 D COMMON STOCK 2010-08-04 4 S 0 100 43.06 D 8100 D COMMON STOCK 2010-08-04 4 S 0 100 43.10 D 8000 D OPTION TO PURCHASE COMMON STOCK 9.25 2010-08-03 4 M 0 6900 9.25 D 2005-11-09 2014-11-09 COMMON STOCK 6900 74250 D OPTION TO PURCHASE COMMON STOCK 23.35 2010-08-03 4 M 0 7500 23.35 D 2006-11-01 2015-11-01 Common Stock 7500 66750 D OPTION TO PURCHASE COMMON STOCK 30.17 2010-08-03 4 M 0 430 30.17 D 2007-10-31 2016-10-31 Common Stock 430 66320 D OPTION TO PURCHASE COMMON STOCK 30.17 2010-08-04 4 M 0 7070 30.17 D 2007-10-31 2016-10-31 Common Stock 7070 59250 D OPTION TO PURCHASE COMMON STOCK 29.22 2010-08-04 4 M 0 8750 29.22 D 2008-11-06 2017-11-06 Common Stock 8750 50500 D OPTION TO PURCHASE COMMON STOCK 27.635 2010-08-04 4 M 0 4000 27.635 D 2009-11-03 2018-11-03 Common Stock 4000 46500 D On June 2, 2010, the common stock of Lufkin Industries, Inc split 2-for-1, resulting in the reporting person's acquisition of 4,000 additional shares of common stock. The option was previously reported as covering 3,450 shares at an exercise price of $18.50 per share, but was adjusted to reflect a stock split that occurred on June 2, 2010. The option was previously reported as covering 3,750 shares at an exercise price of $46.70 per share, but was adjusted to reflect a stock split that occurred on June 2, 2010. The option was previously reported as covering 5,625 shares at an exercise price of $60.34 per share, but was adjusted to reflect a stock split that occurred on June 2, 2010. The option was previously reported as covering 8,750 shares at an exercise price of $58.44 per share, but was adjusted to reflect a stock split that occurred on June 2, 2010. The option was previously reported as covering 8,000 shares at an exercise price of $55.27 per share, but was adjusted to reflect a stock split that occurred on June 2, 2010. Paul G. Perez 2010-08-06