Wells Fargo & Co. announced today it reached an agreement to buy the Wachovia Corp. for about $15.1 billion in stock. Citigroup had agreed to buy Wachovia’s banking operations for $2.2 billion, but Wachovia rejected the deal in favor of one where the entire company would be acquired. In the agreement, Wachovia shareholders will receive 0.1991 shares of Wells Fargo stock in exchange for each share of Wachovia stock. The transaction is valued at $7 a share, based on Wells Fargo’s closing stock price of $35.16 yesterday. The Federal Reserve, however, has not yet reviewed Wells Fargo’s proposal to buy Wachovia.