SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                  SCHEDULE 13G

             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13d-1(b),(c), AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)

                               (Amendment No. 1)*

                           Acacia Research Corporation
--------------------------------------------------------------------------------
                                (Name of Issuer)

            Acacia Research Corporation Common Stock, $.001 par value
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    003881307
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                December 31, 2008
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

     Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

          [_]  Rule 13d-1(b)

          [X]  Rule 13d-1(c)

          [_]  Rule 13d-1(d)

----------
(*)  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 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).


CUSIP No. 003881307
          ---------

1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Kingdon Capital Management, LLC

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  [_]
                                                                        (b)  [_]

3.   SEC USE ONLY

4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.   SOLE VOTING POWER

     0

6.   SHARED VOTING POWER

     1,894,004

7.   SOLE DISPOSITIVE POWER

     0

8.   SHARED DISPOSITIVE POWER

     1,894,004

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,894,004

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

                                                                             [_]

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     6.13%

12.  TYPE OF REPORTING PERSON*

     OO


CUSIP No. 003881307
          ---------

1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Mark Kingdon

2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                        (a)  [_]
                                                                        (b)  [_]

3.   SEC USE ONLY

4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     United States of America

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH

5.   SOLE VOTING POWER

     0

6.   SHARED VOTING POWER

     1,894,004

7.   SOLE DISPOSITIVE POWER

     0

8.   SHARED DISPOSITIVE POWER

     1,894,004

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     1,894,004

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

                                                                             [_]

11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     6.13%

12.  TYPE OF REPORTING PERSON*

     IN


CUSIP No. 003881307
          ---------

Item 1(a).  Name of Issuer:

            Acacia Research Corporation
            --------------------------------------------------------------------

Item 1(b).  Address of Issuer's Principal Executive Offices:

            500 Newport Center Drive
            Newport Beach, CA 92660
            United States of America
            --------------------------------------------------------------------

Item 2(a).  Name of Persons Filing:

            Kingdon Capital Management, LLC
            Mark Kingdon
            --------------------------------------------------------------------

Item 2(b).  Address of Principal Business Office, or if None, Residence of
            Persons Filing:

            152 West 57th Street, 50th Floor
            New York, NY 10019
            United States of America
            --------------------------------------------------------------------

Item 2(c).  Citizenship:

            Kingdon Capital Management, LLC: Delaware
            Mark Kingdon: United States of America
            --------------------------------------------------------------------

Item 2(d).  Title of Class of Securities:

            Acacia Research Corporation Common Stock, $.001 par value
            --------------------------------------------------------------------

Item 2(e).  CUSIP Number:

            003881307
            --------------------------------------------------------------------


Item 3. If This Statement is Filed Pursuant to Rule 13d-1(b), or 13d-2(b)
        or (c), Check Whether the Person Filing is a:

     (a)  [_]  Broker or dealer registered under Section 15 of the Exchange Act.

     (b)  [_]  Bank as defined in Section 3(a)(6) of the Exchange Act.

     (c)  [_]  Insurance company as defined in Section 3(a)(19) of the Exchange
               Act.

     (d)  [_]  Investment company registered under Section 8 of the Investment
               Company Act.

     (e)  [_]  An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

     (f)  [_]  An employee benefit plan or endowment fund in accordance with
               Rule 13d-1(b)(1)(ii)(F);

     (g)  [_]  A parent holding company or control person in accordance with
               Rule 13d-1(b)(1)(ii)(G);

     (h)  [_]  A savings association as defined in Section 3(b) of the Federal
               Deposit Insurance Act;

     (i)  [_]  A church plan that is excluded from the definition of an
               investment company under Section 3(c)(14) of the Investment
               Company Act;

     (j)  [_]  Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

Item 4.  Ownership.

     Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

     (a)  Amount beneficially owned:

          Kingdon Capital Management, LLC:  1,894,004
          Mark Kingdon:  1,894,004
          ----------------------------------------------------------------------

     (b)  Percent of class:

          Kingdon Capital Management, LLC: 6.13%
          Mark Kingdon: 6.13%
          ----------------------------------------------------------------------

     (c)  Number of shares as to which such person has:

          (i)  Sole power to vote or to direct the vote
               Kingdon Capital Management, LLC: 0
               Mark Kingdon: 0

          (ii) Shared power to vote or to direct the vote
               Kingdon Capital Management, LLC: 1,894,004
               Mark Kingdon: 1,894,004

         (iii) Sole power to dispose or to direct the disposition of
               Kingdon Capital Management, LLC: 0
               Mark Kingdon: 0

          (iv) Shared power to dispose or to direct the disposition of
               Kingdon Capital Management, LLC: 1,894,004
               Mark Kingdon: 1,894,004

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 [ ].

                                       N/A
          ----------------------------------------------------------------------

Item 6.  Ownership of More Than Five Percent on Behalf of Another Person.

     If any other person is known to have the right to receive or the power to
direct the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified. A listing of the shareholders of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employee benefit plan, pension fund or endowment fund is not required.

                                       N/A
          ----------------------------------------------------------------------

Item 7. Identification and Classification of the Subsidiary Which Acquired
        the Security Being Reported on by the Parent Holding Company or Control
        Person.

     If a parent holding company or Control person has filed this schedule,
pursuant to Rule 13d-1(b)(1)(ii)(G), so indicate under Item 3(g) and attach an
exhibit stating the identity and the Item 3 classification of the relevant
subsidiary. If a parent holding company or control person has filed this
schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating
the identification of the relevant subsidiary.

                                       N/A
          ----------------------------------------------------------------------

Item 8.  Identification and Classification of Members of the Group.

     If a group has filed this schedule pursuant to ss.240.13d-1(b)(1)(ii)(J),
so indicate under Item 3(j) and attach an exhibit stating the identity and Item
3 classification of each member of the group. If a group has filed this schedule
pursuant to ss.240.13d-1(c) or ss.240.13d-1(d), attach an exhibit stating the
identity of each member of the group.

                                       N/A
          ----------------------------------------------------------------------

Item 9.  Notice of Dissolution of Group.

     Notice of dissolution of a group may be furnished as an exhibit stating the
date of the dissolution and that all further filings with respect to
transactions in the security reported on will be filed, if required, by members
of the group, in their individual capacity. See Item 5.

                                       N/A
          ----------------------------------------------------------------------

Item 10.  Certifications.

     By signing below each of the Reporting Persons certifies that, to the best
of its knowledge and belief, the securities referred to above were not acquired
and are not held for the purpose of or with the effect of changing or
influencing the control of the issuer of the securities and were not acquired
and are not held in connection with or as a participant in any transaction
having such purpose or effect.


                                    SIGNATURE

     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.

                                                February 17, 2009
                                                -------------------------
                                                        (Date)


                                                Kingdon Capital Management, LLC

                                                By: /s/ William Walsh
                                                -------------------------
                                                Name: William Walsh
                                                Title: Chief Financial Officer


                                                /s/Mark Kingdon
                                                -------------------------
                                                Mark Kingdon

Note. Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
for whom copies are to be sent.

Attention. Intentional misstatements or omissions of fact constitute federal
criminal violations (see 18 U.S.C. 1001).


                                                                       EXHIBIT A

                                    AGREEMENT

     The undersigned agree that this Schedule 13G Amendment dated February 17,
2009 relating to Acacia Research Corporation Common Stock, $.001 par value of
Acacia Research Corporation, shall be filed on behalf of the undersigned.


                                          Kingdon Capital Management, LLC

                                          By: /s/ William Walsh
                                          -------------------------
                                          Name: William Walsh
                                          Title: Chief Financial Officer


                                          /s/Mark Kingdon
                                          -------------------------
                                          Mark Kingdon

SK 48400 0002 961010