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 M 0 40000 3.12 A 342280 D Common Stock 2007-07-10 4 S 0 100 38.36 D 342180 D Common Stock 2007-07-10 4 S 0 1552 38.37 D 340628 D Common Stock 2007-07-10 4 S 0 317 38.38 D 340311 D Common Stock 2007-07-10 4 S 0 200 38.39 D 340111 D Common Stock 2007-07-10 4 S 0 100 38.40 D 340011 D Common Stock 2007-07-10 4 S 0 1057 38.405 D 338954 D Common Stock 2007-07-10 4 S 0 100 38.43 D 338854 D Common Stock 2007-07-10 4 S 0 200 38.435 D 338654 D Common Stock 2007-07-10 4 S 0 2200 38.44 D 336454 D Common Stock 2007-07-10 4 S 0 100 38.45 D 336354 D Common Stock 2007-07-10 4 S 0 100 38.47 D 336254 D Common Stock 2007-07-10 4 S 0 100 38.349 D 336154 D Common Stock 2007-07-10 4 S 0 500 38.51 D 335654 D Common Stock 2007-07-10 4 S 0 100 38.53 D 335554 D Common Stock 2007-07-10 4 S 0 500 38.54 D 335054 D Common Stock 2007-07-10 4 S 0 100 38.55 D 334954 D Common Stock 2007-07-10 4 S 0 900 38.56 D 334054 D Common Stock 2007-07-10 4 S 0 300 38.58 D 333754 D Common Stock 2007-07-10 4 S 0 100 38.60 D 333654 D Common Stock 2007-07-10 4 S 0 800 38.66 D 332854 D Common Stock 2007-07-10 4 S 0 100 38.67 D 332754 D Common Stock 2007-07-10 4 S 0 106 38.68 D 332648 D Common Stock 2007-07-10 4 S 0 200 38.69 D 332448 D Common Stock 2007-07-10 4 S 0 100 38.70 D 332348 D Common Stock 2007-07-10 4 S 0 179 38.73 D 332169 D Common Stock 2007-07-10 4 S 0 200 38.74 D 331969 D Common Stock 2007-07-10 4 S 0 200 38.75 D 331769 D Common Stock 50583 I By Spouse Common Stock 90686 I as Trustee for The Mark F. O'Neil Qualified Grantor Retained Annuity Trust Non-Qualified Stock Option (right to buy) 3.12 2007-07-10 4 M 0 40000 0.00 D 2006-01-16 2016-01-16 Common Stock 40000 184941 D Includes 251,250 shares of restricted common stock. 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. Due to the SEC's row number limitations this Form 4 is being filed in four parts. This is part 1 of 4 /s/ Eric D. Jacobs as attorney-in-fact for Mark F. O'Neil 2007-07-12