Wall Street banks have failed to keep up with the stock market during its more than five-year boom, falling behind industries such as technology and health care. There were just 32 US financial firms among the world's largest 500 companies by market value when trading closed on Dec 18 in New York. That compares with 41 at the end of 2006, the last full year before the credit crisis. Some companies that remain on the list, such as Citigroup and American International Group, have shrunk to a fraction of the size of tech giants like Apple and Google. Wells Fargo, which gets most of its revenue from consumer, corporate, and real estate lending, is now the most valuable bank in the world. Wells has been doing a better job, in part because it's not as exposed to the capital markets.