INSURED MUNICIPAL SECURITIES TR 48TH DISCOUNT SERIES 21, 497J, 1996-11-26

INSURED MUNICIPAL SECURITIES TR 48TH DISCOUNT SERIES 21
497J, 1996-11-26

Previous: BP PRUDHOE BAY ROYALTY TRUST, SC 13D, 1996-11-26

Next: MUNICIPAL SECURITIES TRUST SERIES 45 & 73RD DISCOUNT SERIES, 497J, 1996-11-26





REICH & TANG DISTRIBUTORS L.P.
600 Fifth Avenue
New York, New York 10020
(212) 830-5400





                                                    November 26, 1996


VIA EDGAR

Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549

                  Re:  Insured Municipal Securities Trust, Series 21
                       File No. 33-28702

Gentlemen:

                  As Sponsors of the above-referenced Trust, we are writing
this letter to certify that:

                  (1) the form of Prospectus that would have been filed under
Rule 497(b) of the Securities Act of 1933, does not differ from that contained
in the most recent Post-Effective Amendment to the Registration Statement on
Form S-6 (the "Registration Statement"), and

                  (2) the text of the most recent Registration Statement was
filed electronically with the Securities and Exchange Commission on October 28,
1996 and became effective October 31, 1996 pursuant to Rule 485(b).

                                        Insured Municipal Securities Trust,
                                        Series 21


                                        REICH & TANG DISTRIBUTORS L.P.
                                        GRUNTAL & CO. INCORPORATED


                                        By:  _________________________________
                                             Peter J. DeMarco
                                             as agent for the Sponsors

C/M  11939.0001 430037.1