MF Global Holdings Ltd may have faced a shortfall in customer funds even as far back as Oct. 27, four days before the U.S. futures brokerage filed for bankruptcy protection, the Wall Street Journal said, citing people familiar with the situation.

Just hours before the bankruptcy filing, MF Global executives told regulators they believed a shortfall had somehow occurred, possibly starting on Oct. 27 or Oct. 28, the sources told the paper.

Customer funds were found to be short by about $200 million on Oct. 27, the paper said.

The CFTC is also examining whether hundreds of millions of dollars in customer accounts were transferred at MF Global during the week that began Oct. 24, the paper said.

According to CFTC, the transfers were not recorded in the firm's general ledger reviewed by exchange officials, the paper said.

MF Global filed for bankruptcy after its bets on European sovereign debt unnerved investors, credit agencies, customers and counterparties, causing liquidity to disappear.

Thereafter, regulators are seeking to find some $600 million missing from the company's customer accounts.

A spokesman for MF Global said last week that the firm is cooperating with regulators and the bankruptcy trustee trying to find the missing money, according to the Journal.

MF Global could not immediately be reached for comment by Reuters outside regular U.S. business hours.

(Reporting by Sakthi Prasad in Bangalore; Editing by Muralikumar Anantharaman)