(Adds Bank of America comment)

NEW YORK, Nov 10 (Reuters) - Bank of America Corp (BAC.N: Quote, Profile, Research) said on Monday it had agreed to assume $16.6 billion of debt and guarantees of Countrywide Financial Corp, which it acquired in July.

Bank of America, the third-largest U.S. bank by assets, said the assumption was in connection with the transfer to it on Friday of substantially all assets and operations of Countrywide and its Countrywide Home Loans unit. It disclosed the matter in a regulatory filing.

In late April, Charlotte, North Carolina-based Bank of America had said it was examining options for Countrywide debt, estimated at around $40 billion. At the time, it said there was no assurance it would redeem, assume or guarantee the debt.

That prompted worries that corporate debt that Bank of America did not take on would be exposed to higher risk of default. Bank of America has moved to assuage such concerns.

"If you were a Countrywide Financial corporate debtholder, we're taking on the obligation to pay you back," Bank of America spokesman Bob Stickler said on Monday.

Countrywide was the largest U.S. mortgage lender before Bank of America bought it for $2.5 billion on July 1. The bank last month said Countrywide added $259 million to third-quarter operating profit.

Bank of America expects by year-end to complete its acquisition of Merrill Lynch & Co MER.N, the Wall Street bank and brokerage.

Shares of Bank of America closed Friday at $20.49 on the New York Stock Exchange. They are down 50 percent this year. (Reporting by Jonathan Stempel; Editing by Lisa Von Ahn and John Wallace)