Wachovia Corp., the fourth-biggest U.S. bank, may buy SouthTrust Corp., Alabama's biggest lender, in an acquisition worth at least $11.5 billion, people familiar with the matter said yesterday.

Talks between the two banks continued through the weekend. Based on the average premium acquirers paid in the five purchases of U.S. regional banks of more than $3 billion since Jan. 1, 2002, SouthTrust may fetch as much as $14 billion, according to data compiled by Bloomberg News.

Buying SouthTrust of Birmingham, Ala., would give Wachovia chief executive officer Kennedy Thompson a bank with $52.7 billion in assets and 712 consumer-banking offices. Thompson is betting on the resilience of the southeastern economy, one of the nation's fastest-growing regions.

"It would give Wachovia a nice deposit base," said Hilary Hayes, who helps manage $4 billion at Victory SBSF Capital Management in New York and does not hold shares of either bank. "SouthTrust's overall franchise is in fairly robust growth markets and they've been one of the few banks over the last few quarters to show growth in the commercial and industrial loans."

Acquirers paid a 22 percent premium in five purchases of U.S. regional banks bigger than $3 billion since Jan. 1, 2002, Bloomberg data show. That would give SouthTrust shareholders about $42.50 a share. Prices have ranged from a low of 2 percent less than the market value to a high of 33 percent more.

Because SouthTrust's price-to-earnings ratio of 16.3 is higher than Wachovia's, which is 13.2, an acquisition would cut Wachovia's earnings per share. The more that Wachovia would pay for SouthTrust, the deeper the earnings would be cut.

In February, Charlotte-based Wachovia said it would open 250 consumer-banking offices in the next six years in Texas cities, including Dallas, Fort Worth, Houston, Austin and San Antonio. SouthTrust holds about 1 percent of the deposits in Texas with 57 offices, according to Federal Deposit Insurance Corp. data. J.P. Morgan Chase & Co. and Bank of America Corp. are the biggest banks in Texas.

"Parts of the country we like are fast-growing," said Thompson, responding to a question about acquisitions, after the company's annual shareholders meeting in April. "That sort of says West and South. Texas is a place where we would do acquisitions."

Buying SouthTrust, which is the No. 4 bank in Florida, would add to Wachovia's position in the state. Wachovia is the second-biggest bank in Florida, behind Bank of America, and combining with SouthTrust would give it about $50 billion in deposits, according to FDIC data. Bank of America has about $53 billion in the state, the data show. SouthTrust would also make Wachovia the No. 2 bank in Alabama by deposits.

SouthTrust is headed by Wallace D. Malone Jr., 67, who has been chairman and chief executive since 1981. The company has four main business units: commercial banking; retail banking; asset management; and capital management, which includes brokerage, trust, investment and insurance services.