Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Dietz Steven J
  2. Issuer Name and Ticker or Trading Symbol
DealerTrack Holdings, Inc. [TRAK]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O DEALERTRACK HOLDINGS, INC., 1111 MARCUS AVENUE, SUITE M04
3. Date of Earliest Transaction (Month/Day/Year)
10/05/2006
(Street)

LAKE SUCCESS, NY 11042
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 10/05/2006   S   1,117,601 D $ 22.667 (1) 1,119,901 I By GRP II, L.P., GRP II Partners, L.P. and GRP II Investors, L.P. (2)
Common Stock               12,000 (3) D  

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Dietz Steven J
C/O DEALERTRACK HOLDINGS, INC.
1111 MARCUS AVENUE, SUITE M04
LAKE SUCCESS, NY 11042
  X      

Signatures

 /s/ Eric D. Jacobs as attorney-in-fact for Steven J. Dietz   10/09/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The shares were sold in an underwritten offering to the public at a price of $23.760 per share (the "Public Offering Price"). The $22.667 price per share realized by the Reporting Person is equal to the Public Offering Price net of an underwriting discount of $1.093 per share.
(2) GRPVC, L.P. ("GRPVC") is the general partner of each of GRP II, L.P. and GRP II Partners, L.P. and GRP Management Services Corp. ("GRP Management Services") is the general partner of GRPVC. Merchant Capital, Inc. is the general partner of GRP II Investors, L.P. and is in turn an indirect wholly-owned subsidiary of Credit Suisse/First Boston, Inc. Mr. Dietz is Vice President of GRP Management Services. Mr. Dietz disclaims beneficial ownership of these shares except to the extent of his pecuniary interest in such shares.
(3) Includes 3,500 shares of restricted common stock.

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