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:   September 20, 1999
(Date of earliest event reported)


                       CITICORP MORTGAGE SECURITIES, INC.
                             (Packager and Servicer)
                  (Issuer in Respect of the REMIC Pass-Through
                        Certificates Series 1999-6)
               (Exact name of registrant as specified in charter)

     Delaware                   333-43167        13-3408713
(State or other juris-         (Commission     (I.R.S. Employer
diction of organization)        File Nos.)     Identification No.)


  909 Third Avenue, New York, New York           10043
(Address of principal executive offices)       (Zip Code)


Registrant's Telephone Number, including area code (212) 559-9583


        (Former name, former address and former fiscal year, if changed
                               since last report.)


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Item 5.        Other Events.

                       CITICORP MORTGAGE SECURITIES, INC.
                 REMIC Pass-Through Certificates, Series 1999-6
                 ----------------------------------------------

         Attached as Exhibit I are the Computational Materials (as defined in
the no-action letter dated May 20, 1994 issued by the Securities and Exchange
Commission to Kidder, Peabody Acceptance Corporation-I, Kidder, Peabody & Co.
Incorporated and Kidder Structured Asset Corporation) and/or Structural Term
Sheets (as defined in the no-action letter dated February 17, 1995 issued by the
Securities and Exchange Commission to the Public Securities Association)
prepared by PaineWebber Incorporated that are required to be filed
pursuant to such letters.


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<PAGE>


Item 7.    Financial Statements and Exhibits.

                    (c) Exhibits

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

(99)                     Computational Materials/Structural Term Sheets prepared
                         by PaineWebber Incorporated

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<PAGE>


                                   SIGNATURES

         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 thereunto duly authorized.


                               CITICORP MORTGAGE SECURITIES, INC.
                                  (Registrant)


                               By:   /s/ Richard D. Sider
                                   -------------------------------
                                         Richard D. Sider
                                         Assistant Secretary


Dated: September 20, 1999


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                                  EXHIBIT INDEX

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

      I            Computational Materials/Structural                 P
                   Term Sheets prepared by PaineWebber
                   Incorporated


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