A consortium that included the Chinese government was the biggest buyer of a 5 percent stake in China Construction Bank Corp sold last month by Bank of America, the Financial Times reported on Sunday.

The State Administration of Foreign Exchange, the National Social Security Fund and Citic Securities bought the CCB shares, the FT said, citing unnamed sources.

The Chinese government role has been a closely guarded secret as it comes amid fears that Chinese bank stocks will raise additional capital and dilute the stakes of current investors, the FT said. There has been concern that loans and other assets held by CCB and other Chinese banks are vulnerable to losses in a possible slowdown of the Chinese economy.

CCB has been the world's second-largest bank by market value.

Bank of America agreed to sell 13.1 billion CCB shares -- half of its stake -- because of its own drive to raise capital to make up for losses from mortgage loans made during the U.S. housing boom. Bank of America, the biggest U.S. bank by assets, will get $8.3 billion cash from the sale.

Trading volume in CCB shares surged after the sale, suggesting to some in the market that about one-third of the shares sold by Bank of America went to hedge funds and other institutional investors.

Temasek Holdings, a Singapore state investor, and Seatown, a related investment firm, were among previously reported buyers of the CCB shares.

(Reporting by David Henry, editing by Maureen Bavdek)