AMERICAN EXPRESS <AXP> MAY SELL SHEARSON STAKE American Express Co said it and its Shearson Lehman Brothers Inc subsidiary have been holding talks on the possible equity investment in Shearson Lehman by <Nippon Life Insurance Co> of Japan. The company said, "The discussions have led to a general understanding by which Nippon Life would purchase a 13 pct equity investment in Shearson Lehman for approximately 530 mln dlrs and American Express, Shearson Lehman and Nippon Life would explore mutually advantageous, nonexclusive business and investment opportunities." The company said a definitive agreement on the matter is subject to a number of conditions, including approval of the American Express board and the Japanese Ministry of Finance. The company said its board is scheduled to meet March 27 for its regular monthly sessions. American Express said it is continuing to evaluate various courses of action of strategic importance to Shearson Lehman in addition to the possible investment by Nippon Life. It said the options range from expanding Shearson's capacity to meet international competition, to broadening further its access to capital. The company also said, "All the courses of action under study reflect the continuing integral role of Shearson Lehman in American Express' worldwide financial services strategy."