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

                                   Form 13F

                              Form 13F COVER PAGE

Report for the Calendar Year or Quarter Ended: September 30, 2011

Check here if Amendment [X]; Amendment Number: 2

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, 13/th/ 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, 2012
-------------------  ---------------  --------------
[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:   2

Form 13F Information Table Value Total:   $ 165,931
                                          ------------
                                          (thousands)

THIS FILING LISTS SECURITIES HOLDINGS REPORTED ON THE FORM 13F FILED ON
NOVEMBER 14, 2011 PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT AND FOR
WHICH THAT CONFIDENTIAL TREATMENT IS NO LONGER NECESSARY.

List of Other Included Managers: NONE



                          FORM 13F INFORMATION TABLE



COLUMN 1                      COLUMN 2 COLUMN 3  COLUMN 4      COLUMN 5       COLUMN 6  COLUMN 7       COLUMN 8
--------                      -------- --------- -------- ------------------ ---------- -------- ---------------------
                                                                                                   VOTING AUTHORITY
                              TITLE OF            VALUE    SHRS OR  SH/ PUT/ INVESTMENT  OTHER   ---------------------
NAME OF ISSUER                 CLASS    CUSIP    [x$1000]  PRN AMT  PRN CALL DISCRETION MANAGERS   SOLE    SHARED NONE
--------------                -------- --------- -------- --------- --- ---- ---------- -------- --------- ------ ----
                                                                                 
* FUSHI COPPERWELD INC          COM    36113E107   3,029    611,900 SH  CALL    SOLE               611,900
* MEDCO HEALTH SOLUTIONS INC    COM    58405U102 162,902  3,474,132 SH          SOLE             3,474,132