X0202 4 2007-07-10 0 0001333513 DealerTrack Holdings, Inc. TRAK 0001342016 ONeil Mark F C/O DEALERTRACK HOLDINGS, INC. 1111 MARCUS AVENUE, SUITE M04 LAKE SUCCESS NY 11042 1 1 0 0 Chairman of Board, Pres. & CEO Common Stock 2007-07-10 4 S 0 200 38.79 D 331569 D Common Stock 2007-07-10 4 S 0 325 38.80 D 331244 D Common Stock 2007-07-10 4 S 0 300 38.81 D 330944 D Common Stock 2007-07-10 4 S 0 100 38.83 D 330844 D Common Stock 2007-07-10 4 S 0 800 38.85 D 330044 D Common Stock 2007-07-10 4 S 0 1900 39.00 D 328144 D Common Stock 2007-07-10 4 S 0 412 39.01 D 327732 D Common Stock 2007-07-10 4 S 0 100 39.02 D 327632 D Common Stock 2007-07-10 4 S 0 200 39.03 D 327432 D Common Stock 2007-07-10 4 S 0 396 39.04 D 327036 D Common Stock 2007-07-10 4 S 0 100 39.045 D 326936 D Common Stock 2007-07-10 4 S 0 800 39.05 D 326136 D Common Stock 2007-07-10 4 S 0 500 39.06 D 325636 D Common Stock 2007-07-10 4 S 0 300 39.07 D 325336 D Common Stock 2007-07-10 4 S 0 500 39.08 D 324836 D Common Stock 2007-07-10 4 S 0 200 39.09 D 324636 D Common Stock 2007-07-10 4 S 0 2200 39.10 D 332436 D Common Stock 2007-07-10 4 S 0 100 39.11 D 322336 D Common Stock 2007-07-10 4 S 0 200 39.12 D 322136 D Common Stock 2007-07-10 4 S 0 1300 39.13 D 320836 D Common Stock 2007-07-10 4 S 0 1338 39.14 D 319498 D Common Stock 2007-07-10 4 S 0 1300 39.15 D 318198 D Common Stock 2007-07-10 4 S 0 800 39.16 D 317398 D Common Stock 2007-07-10 4 S 0 400 39.17 D 316998 D Common Stock 2007-07-10 4 S 0 700 39.18 D 316298 D Common Stock 2007-07-10 4 S 0 300 39.19 D 315998 D Common Stock 2007-07-10 4 S 0 333 39.20 D 315665 D Common Stock 2007-07-10 4 S 0 300 39.21 D 315365 D Common Stock 50583 I By Spouse Common Stock 90686 I as Trustee for The Mark F. O'Neil Qualified Grantor Retained Annuity Trust The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on October 10, 2006 and amended on May 21, 2007. Includes 251,250 shares of restricted common stock. Due to the SEC's row number limitations this Form 4 is being filed in four parts. This is part 2 of 4 /s/ Eric D. Jacobs as attorney-in-fact for Mark F. O'Neil 2007-07-12