Published reports say a key regulator will not participate in the investigation of the collapsed brokerage that was run by his former Goldman Sachs colleague Jon Corzine.

The New York Times says Gary Gensler, Chairman of the Commodity Futures Trading Commission, will no longer investigate MF Global "due to his long acquaintance with Mr. Corzine."

The Associated Press reported Thursday that in 2005 Gensler donated $10,000 to the New Jersey Democratic Party, which helped get Corzine elected as the state's governor later that year.

MF Global collapsed last week after a disastrous bet on European debt. The company told regulators early Monday that hundreds of millions in client funds are missing.