Temasek Holdings has increased its stake in Merrill Lynch & Co Inc to 13.7 percent from 9.4 percent, according to a U.S. regulatory filing.

The Singapore investment company is Merrill's largest shareholder. Bloomberg News reported earlier this month that Temasek had been granted regulatory approval to increase its stake.

Bank of America Corp announced on Sept. 15 that it would buy Merrill Lynch in an all-stock deal expected to close in the 2009 first quarter.

On Monday, Bank of America shares closed at $30.25, valuing Merrill Lynch shares at just under $26, above the $23 to $24 a share Temasek paid for the bulk of its investment in Merrill at the end of last year.

Merrill shares closed down 19 percent on Monday at $22. -- REUTERS