UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934



                           DEALERTRACK HOLDINGS, INC.
                        ---------------------------------
                                (Name of Issuer)


                                  Common Stock
                                  ------------
                         (Title of Class of Securities)


                                    242309102
                                    ---------
                                 (CUSIP Number)

Check the following box if a fee is being paid with this statement [X]. (A fee
is not required only if the filing person: (1) has a previous statement on file
reporting beneficial ownership of, more than five percent of the class of,
securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7.)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).




                                  Schedule 13G

CUSIP No. 242309102

- ---------------------------------------------------------------------
   1   NAME OF REPORTING PERSON AND SS OR IRS IDENTIFICATION NO. OF
       PERSON

       Fred Alger Management, Inc.      13-2510833
       Fred M. Alger III                378-40-9572
- ---------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                             (a) [ ]
                                                             (b) [ ]

- ---------------------------------------------------------------------
   3   SEC USE ONLY

- ---------------------------------------------------------------------
   4   CITIZENSHIP OR PLACE OF ORGANIZATION
            New York, New York

- ---------------------------------------------------------------------
                  5    SOLE VOTING POWER
     SHARES              1,810,000
  BENEFICIALLY    -----------------------------------------------------
    OWNED BY      6    SHARED VOTING POWER
      EACH               -0-
   REPORTING      -----------------------------------------------------
     PERSON       7    SOLE DISPOSITIVE POWER
      WITH             1,810,000
                  -----------------------------------------------------
                  8    SHARED DISPOSITIVE POWER
                         -0-

- ---------------------------------------------------------------------
   9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                         1,810,000

- ---------------------------------------------------------------------
  10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
       SHARES*

- ---------------------------------------------------------------------
  11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

                         5.35%

- ---------------------------------------------------------------------

  12   TYPE OF REPORTING PERSON*

        Fred Alger Management, Inc.     IA
        Fred M. Alger III               HC




                                  SCHEDULE 13G

ITEM 1(A).  NAME OF ISSUER:
            DEALERTRACK HOLDINGS, INC.


ITEM 1(B).  ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:
              1111 Marcus Avenue
              Suite M04
              Lake Success, New York 11042

ITEM 2(A).  NAME OF PERSON FILING:
            1. Fred Alger Management, Inc.
            2. Fred M. Alger III



ITEM 2(B).  ADDRESS OF PRINCIPAL BUSINESS OFFICE, OR IF NONE, RESIDENCE:
            1. 111 Fifth Avenue, New York, NY 10003
            2. 111 Fifth Avenue, New York, NY 10003

ITEM 2(C).  CITIZENSHIP:
            1. New York
            2. St. Kitts

ITEM 2(D).  TITLE OF CLASS OF SECURITIES:
            Common Stock

ITEM 2(E).  CUSIP NUMBER:
            242309102

ITEM 3.     THE PERSON FILING IS A:
            Investment Distributor and Investment Distributor Control
            Person.





                                 SCHEDULE 13G


ITEM 4(A).  AMOUNT BENEFICIALLY OWNED:
               1,810,000

ITEM 4(B).  PERCENT OF CLASS:
               5.35%

ITEM 4(C).  NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:

           (1)       sole power to vote or to direct the vote 1,810,000

           (ii)      shared power to vote or to direct the vote
                         -0-

           (iii)     sole power to dispose or to direct the disposition of
                     1,810,000

           (iv)      shared power to dispose or to direct the disposition of
                         -0-

ITEM 5.     OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

                  If this statement is being filed to report the fact that as of
                  the date hereof the reporting person has ceased to be the
                  beneficial owner of more than five percent of the class of
                  securities, check the following [ ].

ITEM 6.     OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

               n/a

ITEM 7.     IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
            ACQUIRED THE SECURITIES BEING REPORTED ON BY THE PARENT
            HOLDING COMPANY.

               n/a





                            SCHEDULE 13G


ITEM 8.     IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP:
               Fred Alger Management, Inc.        IA
               Fred M. Alger III                  HC


ITEM 9.     NOTICE OF DISSOLUTION OF GROUP.



ITEM 10.    CERTIFICATION.

                 By signing below I certify that, to the best of my knowledge
and belief, the securities referred to above were acquired in the ordinary
course of business and were not acquired for the purpose of, and do not have the
effect of, changing or influencing the control of the issuer of such securities
and were not acquired in connection with or as a participant in any transaction
having such purposes or effect.

                 After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this statement is true,
complete and correct.

                                 By: Hal Liebes



                                 -------------------------------
                                 Hal Liebes
                                 Executive Vice President

                                 DATE: February 10, 2006





                                 By: /s/ Frederick A. Blum



                                 -------------------------------
                                 Frederick A. Blum,
                                 Attorney-in-Fact

                                 DATE: February 10, 2006