1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 13) TRANSATLANTIC HOLDINGS, INC. - ------------------------------------------------------------------------------- (Name of Issuer) COMMON STOCK, PAR VALUE $1.00 PER SHARE - ------------------------------------------------------------------------------- (Title of Class of Securities) 893521 10 4 ----------------------------------------- (CUSIP Number) KATHLEEN E. SHANNON VICE PRESIDENT AND SECRETARY AMERICAN INTERNATIONAL GROUP, INC. 70 PINE STREET, NEW YORK, NEW YORK 10270 (212) 770-5123 - ------------------------------------------------------------------------------- (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) SEPTEMBER 10, 1999 ------------------------------------------------------- (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 which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(b)(3) or (4), check the following box / /. 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.

2 SCHEDULE 13D CUSIP No. 893521 10 4 PAGE 2 of 7 PAGES 1 NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AMERICAN INTERNATIONAL GROUP, INC. IRS NO. 13-2592361 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) / / (B) / / 3 SEC USE ONLY 4 SOURCE OF FUNDS WC 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or (e) / / 6 CITIZENSHIP OR PLACE OF ORGANIZATION INCORPORATED IN THE STATE OF DELAWARE 7 SOLE VOTING POWER NUMBER OF 8,513,468 SHARES BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 20,256,920 EACH REPORTING 9 SOLE DISPOSITIVE POWER PERSON 8,513,468 WITH 10 SHARED DISPOSITIVE POWER 20,256,920 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 20,256,920 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES / / 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 58.4 14 TYPE OF REPORTING PERSON HC, CO

3 SCHEDULE 13D CUSIP No. 893521 10 4 PAGE 3 of 7 PAGES 1 NAME OF REPORTING PERSON S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON AMERICAN HOME ASSURANCE COMPANY IRS ID# 13-5124990 2 CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) / / (B) / / 3 SEC USE ONLY 4 SOURCE OF FUNDS WC 5 CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or (e) / / 6 CITIZENSHIP OR PLACE OF ORGANIZATION INCORPORATED IN THE STATE OF NEW YORK 7 SOLE VOTING POWER NUMBER OF SHARES BENEFICIALLY 8 SHARED VOTING POWER OWNED BY 11,743,452 EACH REPORTING 9 SOLE DISPOSITIVE POWER PERSON WITH 10 SHARED DISPOSITIVE POWER 11,743,452 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 11,743,452 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES / / 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 33.8 14 TYPE OF REPORTING PERSON IC, CO

4 ITEM 1. Security and Issuer. This Statement relates to the common stock, par value $1.00 per share ("Common Stock"), of Transatlantic Holdings, Inc., a Delaware corporation ("Company"). This Statement amends and supplements Items 1, 3 and 5 of the Statement on Schedule 13D dated August 13, 1991, Amendment No. 1 to such Schedule 13D dated November 3, 1993, Amendment No. 2 to such Schedule 13D dated March 4, 1994, Amendment No. 3 to such Schedule 13D dated March 31, 1994, Amendment No. 4 to such Schedule 13D dated November 21, 1995, Amendment No. 5 to such Schedule 13D dated July 9, 1998, Amendment No. 6 to such Schedule 13D dated August 7, 1998, Amendment No. 7 to such Schedule 13D dated September 11, 1998, Amendment No. 8 to such Schedule 13D dated January 19, 1999, Amendment No. 9 to such Schedule 13D dated March 4, 1999, Amendment No. 10 to such Schedule 13D dated March 11, 1999, Amendment No. 11 to such Schedule 13D dated April 19, 1999 and Amendment No. 12 to such Schedule 13D dated July 26, 1999 (hereinafter collectively referred to as the "Schedule 13D"), previously filed by American International Group, Inc., a Delaware corporation ("AIG"), on behalf of itself and its wholly owned subsidiary, American Home Assurance Company, a New York corporation ("AHAC"). The principal executive offices of the Company are located at 80 Pine Street, New York, New York 10005. Capitalized terms used herein and not otherwise defined shall have the meaning ascribed to such terms as in the Schedule 13D. Page 4 of 7 Pages

5 ITEM 3. Source and Amount of Funds or Other Consideration. During the period from July 27, 1999 through September 10, 1999, AIG purchased 419,400 additional shares of Common Stock at prices ranging from $72.2500 to $74.7500 per share. AIG used its available working capital to purchase the shares of Common Stock. ITEM 5. Interest in Securities of Issuer. (a) and (b). The information required by these paragraphs is set forth in Items 7 through 11 and 13 of each of the cover pages to this Amendment No. 13 to Schedule 13D and is based upon the number of shares of Common Stock outstanding on June 30, 1999 (34,712,887), as reported in the Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 1999. Page 5 of 7 Pages

6 (c). Since the filing of Amendment No. 12 to Schedule 13D dated July 26, 1999, AIG has acquired 419,400 shares of Common Stock as follows: Date Number of Shares Purchased Price Per Share ---- -------------------------- --------------- 07/27/99 112,400 74.2500 07/28/99 37,600 74.7500 08/03/99 500 73.5625 " 7,500 73.6250 " 6,000 73.6875 " 1,100 73.7500 " 4,900 73.8750 08/04/99 1,000 73.0000 " 2,400 73.2500 " 6,600 73.6250 " 1,000 74.0000 08/05/99 2,400 74.0000 " 500 73.8750 " 13,700 73.8125 " 3,400 73.7500 08/06/99 2,000 73.5000 " 7,200 73.8125 " 2,200 73.7500 " 5,800 73.8750 " 1,000 73.9375 " 1,800 74.0000 08/10/99 2,600 74.0000 " 9,700 73.9375 08/11/99 2,000 73.8750 08/12/99 9,000 74.0000 08/13/99 2,000 73.9375 08/16/99 10,000 74.0000 " 1,700 73.6250 08/30/99 4,600 74.0000 08/31/99 20,000 74.0000 09/01/99 300 72.2500 " 200 72.3125 " 500 72.4375 " 500 72.5000 " 500 72.8125 " 500 73.0000 09/02/99 9,300 72.8125 " 1,200 72.7500 09/07/99 13,500 73.2500 " 1,000 73.1250 09/08/99 800 73.2500 " 200 73.1875 09/09/99 1,000 73.0625 " 3,500 73.1875 " 3,700 73.2500 09/10/99 12,100 73.2500 " 600 73.1875 " 87,400 73.1250 The above purchases were made in Open Market Purchases. AIG, AHAC, SICO and Starr and, to the best of AIG's and AHAC's knowledge, the Covered Persons, have not engaged in any transactions in Common Stock within the past 60 days other than those transactions described above. Page 6 of 7 Pages

7 SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated: September 10, 1999 AMERICAN INTERNATIONAL GROUP, INC. By: /s/ KATHLEEN E. SHANNON ------------------------------- Kathleen E. Shannon Vice President and Secretary AMERICAN HOME ASSURANCE COMPANY By: /s/ EDWARD E. MATTHEWS ------------------------------- Edward E. Matthews Senior Vice President Page 7 of 7 Pages