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

                                    FORM 8-K

                                 CURRENT REPORT

                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934

Date of Report:  December 29, 2004
(Date of earliest event reported)



                    Banc of America Mortgage Securities, Inc.
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             (Exact name of registrant as specified in its charter)


      Delaware                          333-118843           36-4514369
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(State or other jurisdiction    (Commission File No.)      (IRS Employer
of incorporation)                                       Identification No.)

      201 North Tryon Street, Charlotte, North Carolina              28255
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Address of principal executive offices                            (Zip Code)

Registrant's telephone number, including area code           (704) 387-8239
                                                    ----------------------------

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          (Former name or former address, if changed since last report)


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

[ ] Written communications pursuant to Rule 425 under the Securities Act (17
CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange
Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange
Act (17 CFR 240.13e-4(c))




ITEM 8.01.    Other Events
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            On December 29, 2004, Banc of America Mortgage Securities, Inc., a
Delaware corporation (the "Registrant"), sold Banc of America Alternative Loan
Trust 2004-12 Mortgage Pass-Through Certificates, Series 2004-12, Class 1-CB-1,
Class 1-CB-R, Class 1-CB-LR, Class 2-CB-1, Class CB-IO, Class 3-A-1, Class
3-IO, Class 3-PO, Class 4-A-1, Class 15-IO, Class 15-PO, Class B-1, Class B-2
and Class B-3 (the "Offered Certificates"), having an aggregate original
principal balance of $339,593,267.00. The Offered Certificates were issued
pursuant to a Pooling and Servicing Agreement, dated December 29, 2004, among
the Registrant, Bank of America, N.A., as servicer ("BANA"), and Wells Fargo
Bank, N.A., as trustee (the "Agreement"), a copy of which is filed as an exhibit
hereto. Mortgage Pass-Through Certificates, Series 2004-12, Class B-4, Class B-5
and Class B-6 Certificates, having an aggregate initial principal balance of
$3,777,278.00 (the "Private Certificates" and, together with the Offered
Certificates, the "Certificates"), were also issued pursuant to the Agreement.

            As of the date of initial issuance, the Offered Certificates
evidenced an approximate 98.90% undivided interest in a trust (the "Trust"),
consisting principally of four pools of fixed interest rate, conventional,
monthly pay, fully-amortizing, one- to four-family residential first mortgage
loans. The remaining undivided interests in the Trust are evidenced by the
Private Certificates distributions on which are subordinated to distributions on
the Offered Certificates.

            Interest on the Offered Certificates will be distributed on each
Distribution Date (as defined in the Agreement). Monthly distributions in
reduction of the principal balance of the Offered Certificates will be allocated
to the Offered Certificates in accordance with the priorities set forth in the
Agreement. Distributions of interest and in reduction of principal balance on
any Distribution Date will be made to the extent that the related Pool
Distribution Amount is sufficient therefor.

            Elections will be made to treat the Trust as two separate REMICs for
federal income tax purposes (the "Lower-Tier REMIC" and "Upper-Tier REMIC" and
each a "REMIC"). The Class 1-CB-1, Class 2-CB-1, Class 3-A-1, Class 3-IO, Class
4-A-1, Class 15-IO, Class 15-PO, Class B-1, Class B-2, Class B-3, Class B-4,
Class B-5 and Class B-6 Certificates and each IO Component and PO Component will
be treated as "regular interests" in the Upper-REMIC and the Class 1-CB-R and
Class 1-CB-LR Certificates will be treated as the "residual interest" in the
Upper-Tier REMIC and "Lower-Tier REMIC, respectively.




ITEM 9.01     Financial Statements and Exhibits
              ---------------------------------

             (c)  Exhibits

Item 601(a)
of Regulation S-K
Exhibit No.                            Description
- -----------                            -----------

      (4)                              Pooling and Servicing Agreement, dated
                                       December 29, 2004, among Banc of America
                                       Mortgage Securities, Inc., Bank of
                                       America, N.A. and Wells Fargo Bank, N.A.,
                                       as trustee.




            Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                       BANC OF AMERICA MORTGAGE
                                         SECURITIES, INC.


December 29, 2004

                                    By:   /s/ Judy Lowman
                                       -----------------------------------------
                                       Name:  Judy Lowman
                                       Title: Vice President




                                INDEX TO EXHIBITS
                                -----------------

                                                              Paper (P) or
Exhibit No.                 Description                       Electronic (E)
- -----------                 -----------                       --------------

   (4)                      Pooling and Servicing Agreement,    E
                            dated December 29, 2004 among
                            Banc of America Mortgage
                            Securities, Inc., Bank of
                            America, N.A. and Wells Fargo
                            Bank, N.A., as trustee.