SBC Communications Inc. is in talks to acquire AT & T; Corp. for at least $15 billion to gain more business clients, according to published reports.

SBC, the number two U.S. telecommunications company, is said to be interested in AT & T;’s lucrative corporate clients, such as Lockheed Martin Corp. and UAL Corp., and its international network.

The merger talks, first reported in The New York Times and The Wall Street Journal, were described as sensitive with a potential for collapse.

The deal may face regulatory hurdles, as AT & T; and SBC are numbers one and two in many consumer markets, meaning the combined company may have to sell its consumer business to win approval.

SBC and AT & T; declined to comment on the reports.

Shares of SBC dropped 2.1 percent to $24.07 in late-morning trading. Shares of AT & T; jumped 6.2 percent to $19.60.