Last Change 03/29 18:30 NEW YORK, March 29 (Reuters) - Citigroup (C) chairman Sandy Weill may be interested in purchasing credit card giant American Express (AXP), according to a report in Business Week magazine. Investors said that Citigroup, with assets of $900 billion and a market value of $230 billion, could potentially afford AmEx, which has assets of $155 billion and a market capitalization of $53 billion, the report said. The article cited a money manager who said that American Express could fetch a total of about $55 per share. Another manager said the company is worth $70 per share. Shares of American Express closed at $38.96 on the New York Stock Exchange on Thursday, below a 52-week high of $62.81 and above a low of $34.25. Morgan Stanley Dean Witter (MWD) and American International Group (AIG) are also in the running for AmEx, the report said. American Express officials were not immediately available for comment.