By Jerry A. DiColo, Jacob Bunge and Dan Strumpf Of DOW JONES NEWSWIRES A group of 10 clearing firms began dividing the former clients of MF Global Holding Ltd.'s (MFGLQ) U.S. brokerage among themselves--one of the first steps by rivals to fill the vacuum left by the huge commodities firm's collapse. Major banks and brokerages such as BNP Paribas S.A. (BNPQY) and Newedge Group shared the stage with niche firms such as Penson Financial Services Inc. in vetting lists of MF Global account holders Thursday morning, according to a person familiar with the process. The effort--spearheaded by CME Group Inc. (CME) after a New York bankruptcy judge approved the action--is an attempt to make progress on unlocking the assets of hundreds of thousands of investors and businesses whose accounts have been largely frozen since MF Global filed for bankruptcy Monday. The 10 firms will receive bulk transfers of segregated-client accounts and distribute some funds back to those clients. And in the process, the firms will get the first crack at former customers of one of the largest commodities broker-dealers in the U.S. Investors that haven't had access to their open trading positions, or bets on the market, this week will be able to close out or offset those trades once they post sufficient funds at the new clearing firm. "It's a big relief to be making trades again," said Jack Scoville of Price Futures Group in Chicago. After being locked out of the market all week, Scoville midday Thursday was able resume trading after his open bets were transferred to a new clearing firm and he fulfilled the margin requirements on those positions. The transfers are only the first step in the quest by customers to receive the estimated $5.45 billion in assets currently due them by MF Global. The bankruptcy court approved the movement of some funds in about 50,000 accounts. As of Thursday, only those assets backing open market bets were accessible. Initially, about 60% of customers' margin will move with the corresponding trades in the transfer to other clearing firms, according to a person familiar with the process. In addition to BNP, Newedge and Penson, the other firms receiving funds are Dorman Trading LLC; R.J. O'Brien & Associates LLC; Mizuho Securities USA Inc., a unit of Mizuho Financial Group (MFG); FC Stone LLC; Rosenthal Collins Group LLC; ADM Investor Services Inc., a unit of Archer Daniels Midland Co. (ADM), and Macquarie Futures USA, according to a person familiar with the situation. Interactive Brokers Group Inc. (IBKR), which nearly bought MF Global earlier this week, decided against joining the 10 firms that would be receiving the failed brokerage's accounts. Interactive Brokers said it "reluctantly" declined to join the plan to divide up MF Global's customer base and move them to other firms, Chief Executive Thomas Peterffy said in an email. Peterffy cited potential market exposure and legal risks that could come along with the business, adding that "MF Global put the exchanges and regulators in a very tough position." After the transfer, former MF Global customers would have the option to keep the accounts with the new clearing firm, transfer them elsewhere, or liquidate them. Transferring some of the funds to other clearing firms doesn't necessarily mean that former customers of MF Global will be able to pull out the cash. The new clearing firms are seen asking the failed firm's clients to up their collateral requirements, according to people involved in the process. And clearing firms won't take clients en masse without first analyzing their credit-worthiness and other factors. "Don't forget all those names need to be vetted by your company, you need to run credit on all of them," said a person familiar with the situation at one of the 10 firms. "You're going to look through all those names and say yes to some and no to others." CME Group, the biggest futures market operator in the U.S., is aiming to open the transfer process to other exchanges and trade-clearing facilities operated by IntercontinentalExchange Inc. (ICE), Depository Trust & Clearing Corp., NYSE Euronext (NYX) and the OCC, which clears trades on all U.S. stock-option markets, according to a person involved in the process. Earlier this week, steps toward the fund transfer were met with confusion by clearing firms and MF Global customers alike. Investors scrambled to learn their options from a myriad of sources including CME, market regulators, MF Global and other clearing firms. On Tuesday, clearing firms were invited to view a list of MF Global clients in order to begin the process of transferring accounts, according to another person involved with the process. But the firms weren't given enough information to judge the credit-worthiness of the prospective clients. "It was literally a list of names, without positions," said the person. "The information was useless." For most of the week, floor traders, small investors and even large commodity hedge funds spent tortuous days trying to speed the process of regaining money that was in MF Global accounts. "We're in a state of anger and shock," said Davide Accomazzo, chief investment officer at Cervino Capital, which has about $5 million tied up at MF Global. "We're trying to access information from everywhere. We're talking to our trading desk," he said. "In terms of official news, we're relying on the website that the official trustee has put up...but it's complete confusion." EMC Master Fund--which invests in commodity futures and options--filed a motion late Wednesday urging the bankruptcy judge overseeing the MF Global liquidation to allow cash funds backing its trading positions to be transferred to a new clearing firm, Peregrine Financial Group, or PFG. The fund said it faces "substantial, if not total, losses" if it isn't allowed to quickly transfer funds frozen in MF Global accounts. EMC's filing said the trustee responsible for the transfer of accounts allowed EMC to move its market bets, but not its cash, to PFG. Without such cash, the fund will be unable to meet margin requirements on its positions and "will be forced to abandon the trading strategy for the positions, which may result in substantial losses," the fund said in the filing. On Thursday, the EMC motion was denied. EMC declined to comment. For others, just receiving the funds backing open bets was seen as progress. -By Jerry A. DiColo, Dow Jones Newswires; 212-416-2155; firstname.lastname@example.org --Tatyana Shumsky and Leslie Josephs contributed to this article.