Citigroup (C) shares fell 2% in premarket trading after a report noted that the investment bank suffered a sharp drop in trading revenue due to a worse-than-expected slowdown in markets business over the summer, reported MarketWatch.

The Financial Times cited people familiar with conversations between the bank and investors, saying some investors believe income could fall by much more than 10%. The bank is expected to report third-quarter earnings on Oct. 15. The FT reported that Citi also has the biggest exposure out of any U.S. bank to emerging markets, which have seen capital flight and currencies dropping in recent months.