May 31 (Reuters) - Shares in U.S. banks tumbled on Wednesday with the S&P 500 bank index hitting its lowest level since early December after JPMorgan Chase and Bank of America Corp warned of revenue weakness in the current quarter.
The bank index was last down 1.72 percent and hit its lowest point since Dec. 5.
Bank of America, JPMorgan and Citigroup Corp were the biggest drags on the S&P 500, with more than 2 percent declines each.
JPMorgan's trading revenue has fallen 15 percent so far in the second quarter, the bank's Chief Financial Officer Marianne Lake told investors at a conference. She would not give a prediction for June.
Bank of America's chief executive meanwhile told investors the bank's second-quarter trading revenue would be lower than a year ago.
"It's especially difficult because of the year-over-year comparison. The first and second quarter in 2016 were fairly busy on the trading front," said RJ Grant, head of trading at Keefe, Bruyette & Woods in New York.
Investors were disappointed that JPMorgan's CFO did not predict a turnaround for June, said Grant.
"People are digging in for a bit of a slower summer here," he said. "If the big banks don't see anything on the horizon then it potentially does not bode well for others. Volatility is non-existent. Its difficult to generate trading volumes or commissions or when the VIX is at historically low levels."
The U.S. stock market's main gauge of investor anxiety closed at its lowest level in over two decades on May 8. The CBOE Volatility Index was up 4.8 percent at 10.88 on Wednesday.
JPMorgan shares were last down 1.8 percent at $82.41 after hitting their lowest level since Dec. 2, with trading volume 0.6 times the 10-day moving average.
Bank of America shares were down 2.3 percent at $22.31 after earlier hitting a low of $22.09, also in heavy trading.
Huntington Bancshares Inc was the biggest percentage loser in the bank subsector with a 2.7 percent drop. (Reporting By Sinead Carew; Editing by Meredith Mazzilli)