Bank of America has reached an agreement to sell an approximately $880 million portfolio of commercial mortgages at a discount of 20% to 25% off the face value, according to a person familiar with the deal. A venture of Square Mile Capital Management LLC, Invesco Ltd. and a fund managed by Canyon Capital Realty Advisors LLC is buying the portfolio, a mix of performing and nonperforming loans tied to 32 properties, the person said. The buildings include the eight-story Renaissance Centre office building in Wilmington, Del., and the Bank of America Tower in St. Louis, which is not owned by the bank. The deal is among the largest commercial mortgage portfolio sales of the year, coming as many banks continue to shed loans made during the market’s peak.