UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D UNDER THE SECURITIES EXCHANGE ACT OF 1934 (AMENDMENT NO. 34)* TUBOS DE ACERO DE MEXICO S.A. (Name of Issuer) Common Stock (Title of Class of Securities) 898592506 (CUSIP Number) Mr. Fernando R. Mantilla Av. Leandro N. Alem 1067, 27th Floor, 1001 - Buenos Aires, Argentina (54-11) 4018-2245 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) November 11, 2002 (Date of Event which Requires Filing of this Statement) If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Sections 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. [ ] NOTE: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Section 240.13d-7 for other parties to whom copies are to be sent. *The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page. The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). ROBERTO ROCCA 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ....................................................... (b) ....................................................... 3. SEC Use Only........................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization ITALY Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) IN ....................................................................... ....................................................................... ....................................................................... ....................................................................... ....................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). SIDERCA Sociedad Anonima Industrial y Comercial 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ....................................................... (b) ....................................................... 3. SEC Use Only........................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization ARGENTINA Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ....................................................................... ....................................................................... ....................................................................... ....................................................................... ....................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). SIDERCA INTERNATIONAL ApS 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 3. SEC Use Only............................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization DENMARK Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). ROCCA & PARTNERS Sociedad Anonima 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 3. SEC Use Only............................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization BRITISH VIRGIN ISLANDS Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). SAN FAUSTIN N.V. 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 3. SEC Use Only............................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization NETHERLANDS ANTILLES Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). SIDERTUBES S.A. 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ....................................................... (b) ....................................................... 3. SEC Use Only........................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization LUXEMBOURG Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 1. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). I.I.I. INDUSTRIAL INVESTMENTS INC. 2. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 3. SEC Use Only............................................................... 4. Source of Funds (See Instructions) NOT APPLICABLE 5. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 6. Citizenship or Place of Organization BRITISH VIRGIN ISLANDS Number of 7. Sole Voting Power NONE Shares Bene- 8. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 9. Sole Dispositive Power NONE Each Reporting 10. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 11. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 12. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 13. Percent of Class Represented by Amount in Row (11) 50.7719% 14. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 15. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). TENARIS S.A. 16. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 17. SEC Use Only............................................................... 18. Source of Funds (See Instructions) NOT APPLICABLE 19. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 20. Citizenship or Place of Organization LUXEMBOURG Number of 21. Sole Voting Power NONE Shares Bene- 22. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 23. Sole Dispositive Power NONE Each Reporting 24. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 25. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 26. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 27. Percent of Class Represented by Amount in Row (11) 50.7719% 28. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 29. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). INVERTUB S.A. 30. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 31. SEC Use Only............................................................... 32. Source of Funds (See Instructions) NOT APPLICABLE 33. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 34. Citizenship or Place of Organization ARGENTINA Number of 35. Sole Voting Power NONE Shares Bene- 36. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 37. Sole Dispositive Power NONE Each Reporting 38. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 39. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 40. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 41. Percent of Class Represented by Amount in Row (11) 50.7719% 42. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... CUSIP No. 898592506 43. Names of Reporting Persons. I.R.S. Identification Nos. of above persons (entities only). SIDTAM LIMITED 44. Check the Appropriate Box if a Member of a Group (See Instructions) (a) ........................................................... (b) ........................................................... 45. SEC Use Only............................................................... 46. Source of Funds (See Instructions) NOT APPLICABLE 47. Check if Disclosure of Legal Proceedings Is Required Pursuant to Items 2(d) or 2(e).......... 48. Citizenship or Place of Organization BRITISH VIRGIN ISLANDS Number of 49. Sole Voting Power NONE Shares Bene- 50. Shared Voting Power 174,114,015 Shares of TAMSA Common ficially Stock (1 ADR=5 shares) Owned by 51. Sole Dispositive Power NONE Each Reporting 52. Shared Dispositive Power 174,114,015 Shares of TAMSA Person With Common Stock (1 ADR=5 shares) 53. Aggregate Amount Beneficially Owned by Each Reporting Person 174,114,015 54. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions) NOT APPLICABLE 55. Percent of Class Represented by Amount in Row (11) 50.7719% 56. Type of Reporting Person (See Instructions) CO ........................................................................... ........................................................................... ........................................................................... ........................................................................... ........................................................................... AMENDMENT NO. 34 TO SCHEDULE 13D This Amendment No. 34 amends, supplements and restates the Statement on Schedule 13D originally filed on September 24, 1992, as amended ("Schedule 13D"), on behalf of Roberto Rocca, Siderca Sociedad Anonima, Industrial y Comercial ("Siderca SAIC"), and Siderca International ApS ("Siderca ApS"), together with Rocca & Partners S.A. ("Rocca & Partners"), San Faustin N.V. ("San Faustin"), Sidertubes S.A. ("Sidertubes"), I.I.I. Industrial Investments Inc. ("III BVI"), Tenaris S.A. ("Tenaris"), Invertub Sociedad Anonima ("Invertub") and Sidtam Limited ("Sidtam") (collectively, "Reporting Persons"), relating to the common shares, without par value, of Tubos de Acero de Mexico S.A., a Mexican company. Pursuant to Rule 101(a)(2)(ii) of Regulation S-T, this Amendment No. 34 to the Schedule 13D amends and restates, as applicable, as of the date of this Amendment, the entire text of the Schedule 13D, as amended, in connection with the Reporting Persons' first filing of an amendment to the Schedule 13D under the Securities and Exchange Commission's Electronic Data Gathering, Analysis, and Retrieval system. As permitted by the rules and regulations of the Securities and Exchange Commission, the Reporting Persons filed Amendments No.1 through No. 33 to the Schedule 13D in paper format. Item 1. Security and Issuer This statement relates to the shares of common stock, without par value ("TAMSA shares"), (including shares of common stock underlying American Depositary Shares ("ADSs") and represented by American Depositary Receipts ("ADRs")) of Tubos de Acero de Mexico S.A., ("TAMSA"), a Mexican corporation, with its principal executive offices at Edificio Parque Reforma, Campos Eliseos 400-17 Piso, Col. Chapultepec Polanco, 11560 Mexico, D.F., Mexico. Item 2. Identity and Background This statement is filed by Mr. Roberto Rocca, Siderca SAIC, Siderca ApS, together with Rocca & Partners, San Faustin, Sidertubes, III BVI, Tenaris, Invertub and Sidtam. Mr. Roberto Rocca, an Italian citizen, resides in Argentina and has his principal business address at Av. Leandro N. Alem 1067, 29th floor, Buenos Aires, Argentina. He is Honorary Chairman of San Faustin and President of Siderca SAIC. Siderca SAIC, an Argentine corporation, is engaged in the manufacturing of seamless steel pipes. Its principal business offices are at Av. Leandro N. Alem, 1067, Buenos Aires, Argentina. Siderca ApS is a Danish holding company. Its principal offices are located at Ostergade 24A, DK, 1100, Denmark. Rocca & Partners is a British Virgin Islands holding company with its business address at Vanterpool Plaza, 2nd Floor, Wickhams Cay I, Road Town, Tortola, British Virgin Islands. San Faustin is a Netherlands Antilles holding company. Its principal business address is at Berg Arrarat 1, Curacao, Netherlands Antilles. Sidertubes is a Luxembourg holding company with its principal business office at 23 Avenue Monterey, L-2086 Luxembourg. Sidtam Limited, is a British Virgin Islands holding company. Its principal business address it at Vanterpool Plaza, 2nd Floor, Wickhams Cay I, Road Town, British Virgin Islands. As a result of a series of recent corporate reorganization transactions, III BVI, a British Virgin Islands corporation, Tenaris, a Luxembourg corporation, and Invertub, an Argentine corporation, have become beneficial owners of TAMSA Shares. Pursuant to these reorganization transactions, Santa Maria Sociedad Anonima Inversora y Financiera ("Santa Maria"), an indirect subsidiary of San Faustin, approved a spin-off of its assets (including its interest in TAMSA) to Invertub. The spin-off was completed on July 10, 2002. Prior to the spin-off, on December 21, 2001, Sidertubes transferred its shares in Santa Maria to its newly-created subsidiary Tenaris. On August 23, 2002, San Faustin transferred its shares in Sidertubes to its newly created subsidiary III BVI. On October 18, 2002, Sidertubes contributed all its assets and liabilities (including its interest in TAMSA) to Tenaris. III BVI is a British Virgin Islands holding company, with its business address at Vanterpool Plaza, 2nd Floor, Wickhams Cay I, Road Town, British Virgin Islands. Tenaris is a Luxembourg holding company, with its business address at 23, Avenue Monterey, L-2163 Luxembourg. Invertub is an Argentine holding company, with its business address at Av. Leandro N. Alem 1067, 28th Floor, Buenos Aires, Argentina. Information required by subparagraphs (a) through (c) and subparagraphs (f) of Item 2 of Schedule 13D, as such information pertains to the executive officers and directors of Siderca SAIC, Siderca ApS, Rocca & Partners, San Faustin, Sidertubes, III BVI, Tenaris, Invertub and Sidtam is set forth respectively on Schedules A through I and is hereby incorporated herein by reference. None of the Reporting Persons, and to their best knowledge, none of the executive officers or directors of Siderca SAIC, Siderca ApS, Rocca & Partners, San Faustin, Sidertubes, III BVI, Tenaris, Invertub or Sidtam has during the last five years been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws. Item 3. Source and Amount of Funds and Other Consideration All of the funds used for the purchases of TAMSA Shares reported on the various amendments to this Schedule 13D were provided from the working capital of the purchaser. Item 4. Purpose of the Transaction As reported in Amendment No. 33 to the Schedule 13D, on September 13, 2002, Tenaris announced the filing of registration statements, prospectuses and other offering documents with the Argentine Securities Commission ("CNV"), the Mexican Securities and Banking Commission ("CNBV"), the Italian Securities Commission ("Consob") and the U.S. Securities and Exchange Commission ("SEC"), relating to Tenaris's offer to exchange its ordinary shares and ADSs for Class A ordinary shares and ADSs of Siderca SAIC, shares and ADSs of TAMSA and ordinary shares of Dalmine S.p.A (the "Exchange Offer"). Reference is now made to the press release issued by Tenaris on November 11, 2002 announcing the commencement of the Exchange Offer. The Exchange Offer will expire on December 13, 2002, unless extended. Among other conditions, Tenaris will not be required to consummate the Exchange Offer unless a sufficient number of TAMSA's total outstanding shares (in the form of shares or ADSs) are validly tendered and not withdrawn so that, after consummation of the Exchange Offer, Tenaris holds, directly or indirectly, more than 80% of TAMSA's total outstanding common shares (in the form of shares or ADSs). Tenaris has reserved the right to waive or modify this or any of the other conditions in its discretion, subject to certain limitations and applicable law. Item 5. Interest in Securities of the Issuer (a) As of the date of this Amendment No. 34 to the Schedule 13D, Siderca ApS directly held 140,600,900 shares, or approximately 43.8%, Tenaris directly held 23,813,115 shares, or approximately 6.94%, and Sidtam directly held 9,700,000, or approximately 2.83% of TAMSA's total outstanding capital stock. As a result, each of the Reporting Persons is a beneficial owner, for the purposes of Rule 13d-3 under the Exchange Act of 1934, of 174,114,015 common shares of TAMSA, corresponding to 50,7719% of TAMSA's outstanding share capital. (b) Each of the Reporting Persons has the shared power to vote and to dispose of TAMSA Shares beneficially owned by each of the Reporting Persons. (c) Except for transfer of shares among Reporting Persons described in Item 2 above, no transactions in TAMSA Shares have been effected during the past 60 days by any of the Reporting Persons. (d) No other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, TAMSA Shares beneficially owned by any of the Reporting Persons and to which this Schedule relates. (e) Not applicable. Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer To the best of the knowledge of the Reporting Persons, as of the date of this Amendment No. 34 to the Schedule 13D, there are no contracts, arrangements, understandings or relationships (legal or otherwise) among the persons named in Item 2 of Schedule 13D or between such persons and any person with respect to any securities of TAMSA. Item 7. Material to be Filed as Exhibits The press release, dated November 11, 2002, announcing the commencement of the Exchange Offer, filed as an exhibit to Tenaris's tender offer statement on Schedule TO dated November 12, 2002, is incorporated hereby by reference. Powers of attorney for Tenaris S.A., I.I.I. Industrial Investments Inc. and Invertub S.A. are filed as exhibits hereto. Powers of attorney for each of the other Reporting Persons are incorporated by reference into this Amendment to the ones filed as exhibits to Amendment No. 23 to the Schedule 13D of Siderca ApS. The written agreement of the Reporting Persons related to the filing of this Schedule 13D as required by Rule 13d-k(1)(iii) is included in the signature pages hereto and is hereby filed as an exhibit hereto. SCHEDULE A SIDERCA S.A.I.C.
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Roberto Rocca Av. Leandro Alem 1067, Honorary Chairman of Italian Buenos Aires - Argentina San Faustin Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Buenos Aires - Argentina of Tenaris Federico Pena Av. Leandro Alem 1067, Vice President of Santa Argentine Buenos Aires - Argentina Maria S.A.I.F. Gianfelice Rocca Av. Leandro Alem 1067, Chairman of San Faustin Italian Buenos Aires - Argentina Ernesto Cossavella Av. Leandro Alem 1067, Independent Consultant Argentine Buenos Aires - Argentina Bruno Marchettini Av. Leandro Alem 1067, Executive Vice Italian Buenos Aires - Argentina President of Siderar Carlos Franck Av. Leandro Alem 1067, President of Santa Argentine Buenos Aires - Argentina Maria S.A.I.F. Arturo Lisdero Maipu 942 Piso 21 Independent Consultant Argentine Carlos Tramutola Av. Leandro Alem 1067, President of Strat Argentine Buenos Aires - Argentina Consulting Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Faustin Argentine Buenos Aires - Argentina Arnaldo Musich Cordoba 320, Buenos Vice President of Santa Argentine Aires, Argentina Maria S.A.I.F Amadeo Vazquez y Vazquez Av. Leandro Alem 1067, Independent Consultant Argentine Buenos Aires - Argentina Hector Carissimi Av. Del Libertador 3736, Independent Consultant Italian Alternate Director Province of Buenos Aires, Argentina
Guillermo Hang Av. Leandro Alem 1067, Director of Techint Argentine Alternate Director Buenos Aires - Argentina Financial Corp. Martin Recondo Av. Leandro Alem 1067, Chief Legal Counsel of Argentine Alternate Director Buenos Aires - Argentina Siderca
PRESENT PRINCIPAL EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------ ---------------- ---------- ----------- Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Chief Executive Officer Buenos Aires - Argentina of Tenaris Guillermo Noriega Av. Leandro Alem 1067, Chief Operating Officer Argentine Chief Operating Officer Buenos Aires - Argentina of Siderca German Cura Av. Leandro Alem 1067, Export Sales Manager of Argentine Export Sales Manager Buenos Aires - Argentina Siderca Juan Jose Serio Av. Leandro Alem 1067, Planning and Argentine Planning and Buenos Aires - Argentina Administration Director Administration Director of Siderca Jorge Tena Av. Leandro Alem 1067, Production Director of Mexican Production Director Buenos Aires - Argentina Siderca Juan Carlos Bongartz Av. Leandro Alem 1067, Labor Relations Manager Argentine Labor Relations Manager Buenos Aires - Argentina of Siderca Anibal Godoi Av. Leandro Alem 1067, Systems Manager of Argentine Systems Manager Buenos Aires - Argentina Siderca Edgardo Carlos Av. Leandro Alem 1067, Finance Manager of Argentine Finance Manager Buenos Aires - Argentina Siderca Walter Alberto Scommazon Av. Leandro Alem 1067, Quality Control Manager Argentine Quality Control Manager Buenos Aires - Argentina of Siderca Ruben Fidalgo Av. Leandro Alem 1067, Domestic Market Manager Argentine Domestic Market Manager Buenos Aires - Argentina of Siderca
PRESENT PRINCIPAL SUPERVISORY COUNCIL BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------- ---------------- ---------- ----------- Mario Azulay Suipacha 1380 Piso 1(degrees), Independent Consultant Argentine Buenos Aires, Argentina Juan Valdez Follino Av. Leandro Alem 1067, C.P.A. Argentine Buenos Aires - Argentina Alberto Pertini Av. Leandro Alem 1067, Industrial Engineer Argentine Buenos Aires - Argentina Roberto Fernandez Moujan Av. Leandro Alem 1067, Lawyer Argentine Buenos Aires - Argentina SCHEDULE B SIDERCA INTERNATIONAL APS
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Carlos Condorelli Av. Leandro Alem 1067, Chief Financial Officer Argentine Buenos Aires - Argentina of Tenaris Renato Lorenzin Via Emilio Bossi 1, Sole Director of San Italian Assistant Secretary Lugano - Switzerland Faustin Lugano S.A. Leonardo Stazi Av. Leandro Alem 1067, Administrative and Argentine Buenos Aires - Argentina Financial Director of Siderar S.A.I.C. Lars Phillip Comerford C/o Intertrust (Denmark) Director of Intertrust Danish A/S, Ostergade 24A, 1100 (Denmark) A/S Kobenhavn K, Denmark SCHEDULE C ROCCA & PARTNERS
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Roberto Rocca Av. Leandro Alem 1067, Honorary Chairman of Italian Buenos Aires - Argentina San Faustin Roberto Einaudi Via Capuccini 14, Milan, Past Chairman of San Italian Italy Faustin Anna Rocca Bonatti Via Maggiolini 1, Milan, Director of Rocca & Italian Italy Partners Marcella Rocca Gaspar Campos 325, Director of Rocca & Italian Province of Buenos Aires, Partners Argentina
PRESENT PRINCIPAL EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------ ---------------- ---------- ----------- Roberto Rocca Av. Leandro Alem 1067, Honorary Chairman of Italian President Buenos Aires - Argentina San Faustin Roberto Einaudi Via Capuccini 14, Milan, Past Chairman of San Italian Vice President Italy Faustin Guido Bonatti Via Donizetti 57 Financial Advisor Italian Treasurer Milan, Italy Stella Maris Martino Via Maggio 2, Lugano, Secretary of Rocca & Italian Secretary Switzerland Partners Stefano Gnecchi Ruscone Via Maggio 2, Lugano, Economist Italian Assistant Secretary Switzerland Andres Pinero Carlos Pellegrini 1175, Architect Argentine Assistant Secretary 1(degrees)"A" Buenos Aires, Argentina SCHEDULE D SAN FAUSTIN N.V.
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Roberto Rocca Av. Leandro Alem 1067, Honorary Chairman of Italian Buenos Aires - Argentina San Faustin Roberto Einaudi Via Capuccini 14, Milan, Past Chairman of San Italian Italy Faustin Giansandro Bassetti Via La Marmora 1, Milan, Vice Chairman of San Italian Italy Faustin Lucio Bastianini 9A, Plateau de Frontenex, Vice Chairman of San Italian Geneva, Switzerland Faustin Guido Bonatti Via Donizetti 57 Financial Advisor Italian Milan, Italy Roberto Bonatti Av. Leandro Alem 1067, President of San Faustin Italian Buenos Aires - Argentina Marco Drago Via G. da Verrazano 15, Chief Executive Officer Italian 28100, Novara, Italy of Istituto Geografico De Agostini, Novara Vincenzo Figus Via Parigi 11, Rome, Italy General Counsel of San Italian Faustin Franco Grandi Rua 7 de Abril 277, San Private investor Italian Pablo, Brazil Gianfelice Rocca Av. Leandro Alem 1067, Chairman of San Faustin Italian Buenos Aires - Argentina Ludovico Rocca Av. Leandro Alem 1067, Director of San Faustin Italian Buenos Aires - Argentina Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Buenos Aires - Argentina of Tenaris
PRESENT PRINCIPAL EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------ ---------------- ---------- ----------- Gianfelice Rocca Av. Leandro Alem 1067, Chairman of San Faustin Italian Chairman Buenos Aires - Argentina Giansandro Bassetti Via La Marmora 1, Milan, Vice Chairman of San Italian Vice Chairman Italy Faustin Lucio Bastianini 9A, Plateau de Frontenex, Vice Chairman of San Italian Vice Chairman Geneva, Switzerland Faustin Roberto Einaudi Via Capuccini 14, Milan, Past Chairman of San Italian Past Chairman Italy Faustin Roberto Rocca Av. Leandro Alem 1067, Honorary Chairman of Italian Honorary Chairman Buenos Aires - Argentina San Faustin Roberto Bonatti Av. Leandro Alem 1067, President of San Faustin Italian President Buenos Aires - Argentina Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Vice President Buenos Aires - Argentina of Tenaris Carlos Enrique Zandona Av. Leandro Alem 1067, Treasurer of San Faustin Argentine Treasurer Buenos Aires - Argentina Pierluigi Molajoni Av. Leandro Alem 1067, President, Techint Italian General Manager Buenos Aires - Argentina Engineering Company Inc. Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Faustin Argentine Secretary Buenos Aires - Argentina Umberto Bocchini Av. Leandro Alem 1067, In-house Lawyer Italian Assistant Secretary Buenos Aires - Argentina Stefano Gnecchi Ruscone Via Maggio 2, Lugano, Economist Italian Assistant Secretary Switzerland SCHEDULE E SIDERTUBES S.A.
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Giansandro Bassetti Via La Marmora 1, Milan, Vice Chairman of San Italian Italy Faustin Lucio Bastianini 9A, Plateau de Frontenex, Vice Chairman of San Italian Geneva, Switzerland Faustin Roberto Bonatti Av. Leandro Alem 1067, President of San Faustin Italian Buenos Aires - Argentina Gianfelice Rocca Av. Leandro Alem 1067, Chairman of San Faustin Italian Buenos Aires - Argentina Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Buenos Aires - Argentina of Tenaris Carlos Enrique Zandona Av. Leandro Alem 1067, Treasurer of San Faustin Argentine Buenos Aires - Argentina SCHEDULE F I.I.I. INDUSTRIAL INVESTMENTS INC.
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Roberto Bonatti Av. Leandro Alem 1067, President of San Faustin Italian Buenos Aires - Argentina Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Faustin Argentine Buenos Aires - Argentina Carlos Enrique Zandona Av. Leandro Alem 1067, Treasurer of San Faustin Argentine Buenos Aires - Argentina
PRESENT PRINCIPAL CITIZENSHIP EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION - ------------------ ---------------- ---------- Roberto Bonatti Av. Leandro Alem 1067, President of San Faustin Italian President Buenos Aires - Argentina Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Faustin Argentine Secretary Buenos Aires - Argentina Carlos Enrique Zandona Av. Leandro Alem 1067, Treasurer of San Faustin Argentine Treasurer Buenos Aires - Argentina Umberto Bocchini Av. Leandro Alem 1067, In-house Lawyer Italian Assistant Secretary Buenos Aires - Argentina Renato Lorenzin Via Emilio Bossi 1, Sole Director of San Italian Assistant Secretary Lugano - Switzerland Faustin Lugano S.A. SCHEDULE G TENARIS S.A.
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Buenos Aires - Argentina of Tenaris Renato Lorenzin Via Emilio Bossi 1, Sole Director of San Italian Lugano - Switzerland Faustin Lugano S.A. Enrico Bonatti Via Monte Rosa 93 Director of Techint Italian Milan, Italy Finanziaria S.r.l. Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Argentine Buenos Aires - Argentina Faustin
PRESENT PRINCIPAL EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------ ---------------- ---------- ----------- Paolo Rocca Av. Leandro Alem 1067, Chief Executive Officer Italian Chief Executive Officer Buenos Aires - Argentina of Tenaris Carlos Condorelli Av. Leandro Alem 1067, Chief Financial Officer Argentine Chief Financial Officer Buenos Aires - Argentina of Tenaris SCHEDULE H INVERTUB SOCIEDAD ANONIMA
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Carlos Franck Av. Leandro Alem 1067, President of Santa Argentine (President) Buenos Aires Argentina Maria S.A.I.F. Carlos Alberto Condorelli Av. Leandro Alem 1067, Chief Financial Officer Argentine Buenos Aires - Argentina of Tenaris Carlos Enrique Zandona Av. Leandro Alem 1067, Treasurer of San Faustin Argentine Buenos Aires Argentina Federico Pena (h) Av. Leandro Alem 1067, Vice President of Santa Argentine (Alternate Director) Buenos Aires - Argentina Maria SAIF. Martin Carlos Arriola Av. L.N. Alem 1067, In-house counsel Argentine Alternate Statutory Buenos Aires-Argentina Auditor Ignacio Maria Casares Av. L.N. Alem 1067, In-house counsel Argentine Alternate Statutory Buenos Aires-Argentina Auditor SCHEDULE I SIDTAM LIMITED
PRESENT PRINCIPAL DIRECTORS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - --------- ---------------- ---------- ----------- Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Faustin Argentine Buenos Aires - Argentina Claudio Gugliuzza Km. 433.7 Carretera Administrative Director Argentine Mexico-Veracruz Via Xalapa of TAMSA Veracruz, 91700 Mexico Leonardo Stazi Av. Leandro Alem 1067, Administrative and Argentine Buenos Aires - Argentina Financial Director of Siderar S.A.I.C. Edgardo Carlos Av. Leandro Alem 1067, Finance Manager of Argentine Buenos Aires - Argentina Siderca
PRESENT PRINCIPAL EXECUTIVE OFFICERS BUSINESS ADDRESS OCCUPATION CITIZENSHIP - ------------------ ---------------- ---------- ----------- Fernando Mantilla Av. Leandro Alem 1067, Secretary of San Argentine President Buenos Aires - Argentina Faustin Mario Lalla Avenida Prosperidade, 374- Administrative and Argentine Treasurer Vila Prosperidade Financial Director of Sao Caetano do Sul - SP Confab Industrial S.A. Brazil Leonardo Stazi Av. Leandro Alem 1067, Administrative and Argentine Secretary Buenos Aires - Argentina Financial Director of Siderar S.A.I.C. Felix Todd Pinero Edificio Parque Reforma, Legal Counsel of Tamsa Mexican Assistant Secretary Campos Eliseos 400, 11560 Mexico, D.F., Mexico Umberto Bocchini Av. Leandro Alem 1067, In-house Lawyer Italian Assistant Secretary Buenos Aires - Argentina [LETTERHEAD OF ROBERTO ROCCA] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by ROBERTO ROCCA to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF ROCCA & PARTNERS, S.A.] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by ROCCA & PARTNERS S.A. to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF SAN FAUSTIN N.V.] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by SAN FAUSTIN N.V. to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF SIDERCA SOCIEDAD ANONIMA INDUSTRIAL Y COMERCIAL] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by SIDERCA Sociedad Anonima Industrial y Comercial to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF SIDERCA INTERNATIONAL APS] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by SIDERCA INTERNATIONAL ApS to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF SIDERTUBES S.A.] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by SIDERTUBES S.A. to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF I.I.I. INDUSTRIAL INVESTMENTS INC.] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by I.I.I. INDUSTRIAL INVESTMENTS Inc. to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., TENARIS S.A., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF TENARIS S.A.] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by TENARIS S.A. to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., INVERTUB Sociedad Anonima, and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF INVERTUB SOCIEDAD ANONIMA] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by INVERTUB Sociedad Anonima to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., and SIDTAM LIMITED. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact [LETTERHEAD OF SIDTAM LIMITED] SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I, Fernando Mantilla, attorney duly authorized by SIDTAM LIMITED to sign this statement, certify that the information set forth in this Schedule 13D is true, complete and correct. Pursuant to Rule 13d- 1 (f) (1), the undersigned joins in the filing of this Schedule 13D on his own behalf and on behalf of ROBERTO ROCCA, ROCCA & PARTNERS S.A., SAN FAUSTIN N.V., SIDERCA Sociedad Anonima Industrial y Comercial, SIDERCA INTERNATIONAL ApS, SIDERTUBES S.A., I.I.I. INDUSTRIAL INVESTMENTS Inc., TENARIS S.A., and INVERTUB Sociedad Anonima. November 14, 2002 /s/ Fernando Mantilla --------------------- Fernando Mantilla Attorney-in-fact TENARIS S.A. Societe Anonyme 23, Avenue Monterey L-2086 LUXEMBOURG POWER OF ATTORNEY The undersigned, Fernando Ricardo Mantilla, Director of TENARIS S.A., a company organized under the laws of Luxembourg, hereby constitutes and appoints CARLOS MANUEL FRANCK, FERNANDO R. MANTILLA AND CARLOS E. ZANDONA, and each of them, as attorneys or attorney of the undersigned with full power of substitution and resubstitution, to sign on its behalf a Statement on Schedule 13D relating to the Common Stock, of TUBOS DE ACERO DE MEXICO S.A., including any agreements attached as exhibits thereto, and to sign any or all amendments to such Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys or attorney, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, hereby ratifying and confirming all that said attorneys or attorney, or any of them or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. By: /s/ Fernando Mantilla Fernando R. Mantilla Director Dated: November 12, 2002 I.I.I. INDUSTRIAL INVESTMENTS INC. BRITISH VIRGIN ISLANDS POWER OF ATTORNEY The undersigned, Roberto Bonatti, President of I.I.I. INDUSTRIAL INVESTMENTS Inc., a company organized under the laws of the British Virgin Islands, hereby constitutes and appoints CARLOS MANUEL FRANCK, FERNANDO R. MANTILLA AND CARLOS E. ZANDONA, and each of them, as attorneys or attorney of the undersigned with full power of substitution and resubstitution, to sign on its behalf a Statement on Schedule 13D relating to the Common Stock, of TUBOS DE ACERO DE MEXICO S.A., including any agreements attached as exhibits thereto, and to sign any or all amendments to such Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys or attorney, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, hereby ratifying and confirming all that said attorneys or attorney, or any of them or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. By: /s/ Roberto Bonatti Roberto Bonatti President Dated: November 12, 2002 INVERTUB S.A. POWER OF ATTORNEY The undersigned, Carlos Manuel Frank, President of INVERTUB Sociedad Anonima, a company organized under the laws of Argentina, hereby constitutes and appoints CARLOS MANUEL FRANCK, FERNANDO R. MANTILLA AND CARLOS E. ZANDONA, and each of them, as attorneys or attorney of the undersigned with full power of substitution and resubstitution, to sign on its behalf a Statement on Schedule 13D relating to the Common Stock, of TUBOS DE ACERO DE MEXICO S.A., including any agreements attached as exhibits thereto, and to sign any or all amendments to such Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys or attorney, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, hereby ratifying and confirming all that said attorneys or attorney, or any of them or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. By: /s/ Carlos M. Franck Carlos M. Franck Director Dated: November 12, 2002