FILED BY TENARIS S.A.
                           PURSUANT TO RULE 425 UNDER THE SECURITIES ACT OF 1933

                                               SUBJECT COMPANY: SIDERCA S.A.I.C.
                                                  EXCHANGE ACT FILE NO.: 1-15188

                                 SUBJECT COMPANY: TUBOS DE ACERO DE MEXICO, S.A.
                                                  EXCHANGE ACT FILE NO.: 1-04870

                COMMISSION FILE NUMBER FOR THE REGISTRATION STATEMENT: 333-99769


[TENARIS PRESS RELEASE LOGO]


Luxembourg, November 22, 2002 - Tenaris S.A. ("Tenaris") informs investors that
on November 18, 2002, Acciones y Valores de Mexico, S.A. de C.V., Casa de Bolsa,
a member of Grupo Financiero Banamex ("Accival") who is acting as the Mexican
Exchange Agent for Tenaris's offer (the "Exchange Offer") to exchange its shares
for shares of Tubos de Acero de Mexico, S.A. ("Tamsa"), has obtained from the
Mexican National Banking and Securities Commission (Comision Nacional Bancaria y
de Valores) the certificate attesting to the satisfaction of certain
requirements required under Mexican tax law for the exchange of Tamsa shares for
Tenaris shares to be exempt from income tax. Accordingly, Accival will not make
any income tax withholdings under Mexican law in connection with any gains
realized by holders of Tamsa shares participating in the Exchange Offer.

This communication is neither an offer to purchase nor a solicitation of an
offer to sell shares or ADSs. The Exchange Offer is made in the United States
solely by the prospectus dated November 8, 2002, and the related forms of
acceptance and ADS letters of transmittal is not being made to, nor will tenders
be accepted from or on behalf of, holders of shares or ADSs in any jurisdiction
in which the making of the exchange offer or acceptance thereof would not be in
compliance with the laws of such jurisdiction. In those jurisdictions where the
applicable laws require that the exchange offer be made by a licensed broker or
dealer, the exchange offer shall be deemed to be made on behalf of the dealer
manager for the Exchange Offer or one or more registered brokers or dealers
licensed under laws of such jurisdiction.