Citi profit slumps on weak trading, investment banking revenue

The profit decline is the biggest among big U.S. banks that have reported first-quarter results so far, but lower operating expenses helped Citigroup beat Wall Street's low expectations. Shares of the No.4 U.S. bank by assets were up more than 2 percent at $46.15 in premarket trading on Friday. Investment banking fees across the industry fell 29 percent in the period, the slowest first-quarter since 2009, according to Reuters data.