THIS FILING LISTS SECURITIES HOLDINGS REPORTED ON THE FORM 13F FILED ON AUGUST
14, 2007 PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT.

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

                                    Form 13F

                               FORM 13F COVER PAGE

Report for the Calendar Year or Quarter Ended:  June 30, 2007
                                              ----------------------------------

Check here if Amendment [X]; Amendment Number:      4
                                              -----------------
This Amendment (Check only one.):             [ ] is a restatement.
                                              [X] adds new holdings entries.

Institutional Investment Manager Filing this Report:

Name:                 Magnetar Financial LLC
Address:              1603 Orrington Avenue
                      13th Floor
                      Evanston, IL  60201

Form 13F File Number:  28-11800
                       --------

The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained herein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this form.

Person Signing this Report on Behalf of Reporting Manager:

Name:                 Michael Turro
Title:                Chief Compliance Officer
Phone:                (847) 905-4690

Signature, Place, and Date of Signing:

     /s/ Michael Turro             Evanston, IL            May 15, 2008
 -------------------------  ------------------------  ----------------------
        [Signature]               [City, State]               [Date]

Report Type (Check only one.):

[X]      13F HOLDINGS REPORT. (Check here if all holdings of this reporting
         manager are reported in this report.)

[_]      13F NOTICE. (Check here if no holdings reported are in this report, and
         all holdings are reported by other reporting manager(s).)

[_]      13F COMBINATION REPORT. (Check here if a portion of the holdings for
         this reporting manager are reported in this report and a portion are
         reported by other reporting manager(s).)








                              FORM 13F SUMMARY PAGE


Report Summary:

Number of Other Included Managers:                          0
                                                -------------------------
Form 13F Information Table Entry Total:                     1
                                                -------------------------
Form 13F Information Table Value Total:                  $30,328
                                                -------------------------
                                                       (thousands)


List of Other Included Managers:

Provide a numbered list of name(s) and Form 13F file number(s) of all
institutional investment managers with respect to which this report is filed,
other than the manager filing this report.

[If there are no entries in this list, state "NONE" and omit the column headings
and list entries.]

None








                                                        MAGNETAR FINANCIAL, LLC
                                                               FORM 13F
                                                      Quarter Ended June 30, 2007



- ------------------------------------------------------------------------------------------------------------------------------------
                  CLASS                  VALUE     SHRS OR PRN    SH/     PUT/   INVESTMENT    OTHER         VOTING AUTHORITY
                  ------                 -----    ------------   ---      ----   ----------    --------      ----------------
NAME OF ISSUER    TITLE     CUSIP      (X$1,000)      AMT        PRN      CALL   DISCRETION    MANAGERS     SOLE    SHARED   NONE
- --------------    -----     -----      ---------      ---        ---      ----   ----------                 ----    ------   ----
- ------------------------------------------------------------------------------------------------------------------------------------
                                                                                            
THOMSON CORP      COM      884903105    30328       742800        SH                SOLE                  742800
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