John Paulson's Paulson & Co. hedge-fund firm bought 168 million shares of Bank of America and took big chunks in other banks during the second quarter, according to a regulatory filing.

Paulson's end-of-second-quarter holdings report with the Securities and Exchange Commission was filed Wednesday. At today's $15.93 (€11.81) closing price, the stake would be worth $2.7bn. Bank of America Merrill Lunch shares were up in aftermarket trading.