One of the Big Four banks in the U.S., Wells Fargo was one of the first to seek to profit from illegal immigration. They sought to open bank accounts for illegal aliens and they've sought to give home loans to illegal aliens (see also mortgage mess). In 2008, WellsFargo bought Wachovia Bank which was arguably even more crooked.
Banks like Wells Fargo seeking profits from illegal activity relates to political corruption; see immigration banks for the details.
See also: Bank of America, Chase Bank, CitiBank, Bank of the West, American Bankers Association, Bank One, Cardinal Bank, Cathay Bank, and City National Bank.