The equity markets had a double sting in the tail for Citigroup in the second quarter, as the bank posted the joint biggest drop in underwriting revenues on Wall Street and saw a surge in trading revenues wiped out by a valuation adjustment.

Citi, in its second-quarter results on Thursday, revealed that revenues from equity underwriting at its institutional client group division sank by 25% year-on-year to $296 million, matching the drop posted on Wednesday by Bank of America Merrill Lynch.