While stock prices jumped Monday, U.S. bank stocks are way down from their highs. And that makes them still a bargain for healthy foreign banks willing to take a chance. Spain's biggest lender, Banco Santander, is buying 75 percent of Penn.-based Sovereign Bancorp. Sovereign has 750 branches and is the largest surviving U.S. savings and loan. Santander already owned a quarter of Sovereign's stock.