LITTLE ROCK — MF Global Holdings Ltd. collapsed last year because of mistakes by Jon Corzine, MF Global’s former chairman and chief executive officer, according to a summary of findings from an investigation led by U.S. House Republicans.

Corzine expanded MF Global into new areas without ensuring its core commodities trading business, according to the findings released Wednesday by Rep. Randy Neugebauer, the Texas Republican and chairman of the U.S. House Financial Services subcommittee that pursued a year-long investigation into the collapse. Corzine, a former U.S. senator, governor of New Jersey and Goldman Sachs Group Inc. co-chairman, has testified to Congress that he doesn’t know what happened to the money.

The summary reflects conclusions reached by Republicans, who hold a majority on the panel and were in contact with Democrats during the investigation, according to Jeff Emerson, spokesman for the Financial Services Committee. The investigation included three congressional hearings, more than 50 interviews and a review of documents from MF Global, former brokerage employees and regulators, according to the summary.

MF Global, which filed for bankruptcy protection Oct. 31, 2011, is returning money to customers who faced a $1.6 billion shortfall as part of the firm’s liquidation.

The Commodities Futures Trading Commission, Securities and Exchange Commission and Justice Department have been investigating the collapse of MF Global. The congressional investigation had trouble determining who was responsible for the gap in client funds, Neugebauer said in an interview last month.

“Those people may be talking to the regulators or law enforcement officials, but they aren’t talking to us and so it makes it difficult for us to make that call,” Neugebauer said in an Oct. 31 interview in Chicago.

Louis Freeh, a trustee for parent company MF Global Holdings Ltd. has been unwinding the parent company under Chapter 11 of the U.S. Bankruptcy Code in an effort to repay creditors. James Giddens, a separate trustee for the failed brokerage, MF Global Inc., is liquidating assets to repay customers under the Securities Investor Protection Act. Each trustee has conducted his own investigation into how the company failed and they have been at odds over whether certain sums belong to creditors or customers.

Steven Goldberg, a New York-based spokesman for Corzine, declined immediate comment.

Information for this article was contributed by Kim Chipman and Tiffany Kary of Bloomberg News.

Business, Pages 28 on 11/15/2012