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

                                   FORM 12b-25


                           NOTIFICATION OF LATE FILING

                           SEC File Number: 001-16107
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           (Check one) [ ]Form 10-K [ ]Form 20-F [ ]Form 11-K
                       [X]Form 10-Q [ ]Form N-SAR

For Period Ended: March 31, 2003

[ ] Transition Report on Form 10-K
[ ] Transition Report on Form 20-F
[ ] Transition Report on Form 11-K
[ ] Transition Report on Form 10-Q
[ ] Transition Report on Form N-SAR
For the Transition Period Ended: ___________________

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Read  Instruction  (on back page) Before  Preparing  Form,  Please Print or Type
Nothing  in this  form  shall be  construed  to imply  that the  Commission  has
verified any information contained herein.

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      If the notification relates to a portion of the filing checked above,
           identify the Item(s) to which the notification relates: N/A
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PART I -- REGISTRANT INFORMATION

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Full Name of Registrant: Mirant Corporation
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Former Name if Applicable: Southern Energy Inc.

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Address of Principal Executive Office (Street and Number, City)
1155 Perimeter Center West, Atlanta, Georgia 30338-5414

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PART II -- RULES 12b-25(b) AND (c)

If the subject report could not be filed without  unreasonable effort or expense
and the registrant seeks relief pursuant to Rule 12b-25(b), the following should
be completed. (Check box if appropriate)

     (a) The reasons  described  in  reasonable  detail in Part III of this form
     could not be eliminated  without  unreasonable  effort or expense;  (b) The
     subject annual report,  semi-annual report, transition report on Form 10-K,
     Form 20-F,11-K or Form N-SAR, or portion  thereof,  will be filed [ ] on or
     before the fifteenth calendar day following the prescribed due date; or the
     subject  quarterly  report of  transition  report on Form 10-Q,  or portion
     thereof  will be filed on or before the fifth  calendar day  following  the
     prescribed  due date; and (c) The  accountant's  statement or other exhibit
     required by Rule 12b-25(c) has been attached if applicable.

PART III - NARRATIVE

The audit of the Company's  2002  financial  statements  and the reaudits of the
Company's  2000 and 2001 financial  statements  were completed on April 29, 2003
which  delayed the  Company's  ability to begin  focusing  on the 1st  quarter's
financial  information  and Form 10-Q.  As such,  we were unable to complete the
preparation  and review of our 1st quarter 2003 Form 10-Q by the required filing
date without unreasonable cost and effort.


PART IV-- OTHER INFORMATION

(1)  Name  and  telephone  number  of  person  to  contact  in  regard  to  this
notification

   Dan Streek                       678                        579-5000
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      (Name)                   (Area Code)                (Telephone Number)

(2) Have all other  periodic  reports  required under Section 13 or 15(d) of the
Securities  Exchange Act of 1934 or Section 30 of the Investment  Company Act of
1940  during  the  preceding  12  months  or for such  shorter  period  that the
registrant  was  required to file such  report(s)  been filed?  If answer is no,
identify report(s). [ ]Yes [X]No

The Company  filed its Form 10-K for the year ended  December  31, 2003  without
including the interim financial  information  required by Item 302 of Regulation
S-K.

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(3) Is it anticipated that any significant  change in results of operations from
the  corresponding  period for the last  fiscal  year will be  reflected  by the
earnings  statements to be included in the subject report or portion thereof?
[ ]Yes [X]No

If so, attach an explanation of the  anticipated  change,  both  narratively and
quantitatively, and, if appropriate, state the reasons why a reasonable estimate
of the results cannot be made.

                               Mirant Corporation
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                  (Name of Registrant as Specified in Charter)

has caused this notification to be signed on its behalf by the undersigned
hereunto duly authorized.



Date: May 15, 2003                        By /s/ Dan Streek
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                                             Dan Streek, Vice President and
                                             Controller
                                             (Principal Accounting Officer)