WASHINGTON — After two years of secrecy, the Federal Reserve Bank of New York is disclosing key details about billions of dollars of financial products it bought while rescuing insurance giant American International Group Inc. and supporting the sale of failed investment bank Bear Stearns.

The New York Fed on Wednesday released the names of the securities held by three companies it created to buy toxic derivatives, mortgage loans and mortgage-backed bonds from Bear Stearns, AIG and AIG’s business partners. The New York Fed also revealed their current values.

These toxic mortgage assets were central to the 2008 financial crisis. Their values often are based on the values of thousands of underlying mortgage loans. As homeowners started defaulting on risky subprime mortgages in record numbers, banks didn’t know how much the mortgage-backed bonds were worth. That made it nearly impossible to sell or trade the assets.

When Bear Stearns teetered in March 2008, the New York Fed brokered the firm’s sale to JPMorgan Chase & Co. The New York Fed created Maiden Lane LLC to buy $30 billion of financial instruments that JPMorgan was unwilling to take over.

The New York Fed created Maiden Lane II LLC and Maiden Lane III LLC to support the $182 billion AIG rescue. The former bought mortgage-backed bonds from AIG’s insurance subsidiaries. The latter bought securities from AIG’s business partners.