A top Securities and Exchange Commission official said yesterday that customers could lose as much as $198 million in the wake of the bankruptcy of Bevill, Bresler & Schulman Asset Management Corp., a New Jersey-based government securities firm that dealt largely with savings and loan associations.

Ira Lee Sorkin, the SEC's New York regional administrator, said in a telephone interview that an SEC trustee has just begun to sort out the records of Asset Management Corp. and two other affiliated firms. Until the trustee finishes, it will be impossible to determine exactly how much individual customers of the firm stand to lose, Sorkin said.

Four years ago, the dealer, two affiliated companies that share the Bevill, Bresler & Schulman name and several of their principals were suspended from doing business for 60 days after the SEC alleged that the companies made misleading statements to investors, violated antifraud provisions of the securities code and failed to supervise their employes.

The SEC had tried but failed to take action against E.S.M. Government Securities Inc., the government securities dealer that failed last month. E.S.M.'s failure cost its customers about $315 million and sparked a run on privately insured savings and loan associations in Ohio.

E.S.M. and Bevill, Bresler & Schulman Asset Management Corp. engaged in similiar practices, according to SEC complaints in the cases. The dealers allegedly used for their own purposes government securities they were holding as collateral for loans made to the dealers by their customers.

When it filed for federal bankruptcy protection late Sunday, Asset Management Corp. reported that two Maryland savings and loan associations and the Army Central Banking and Investment Fund were among more than a score of customers that could lose money as a result of their dealings with the securities trader.

The petition said that Merritt Commercial Savings and Loan Association of Baltimore is owed $2.2 million and the Army Fund -- which controls a pool of unappropriated military cash that is used for morale, welfare and recreational programs -- is owed $11 million. Old Court Savings and Loan Association of Baltimore also was identified as a creditor by the dealer, but the amount of its loss was not stated. Both Merritt and Old Court are state-chartered savings and loans insured by the Maryland Savings Share Insurance Corp., a private company.

U.S. District Judge Dickinson Debevoise in Newark yesterday froze the assets of three affiliated companies -- all of which share the name Bevill, Bresler & Schulman -- and put an SEC-nominated trustee in charge of Asset Management Corp. and a receiver in charge of the other two. Sorkin said Sol S. Cohen, a New York financial expert, will be the receiver or trustee for all three companies.

But Debevoise denied the SEC's petition to put the fourth company -- Bevill, Bresler & Schulman Inc. -- under a trustee as well. Bevill, Bresler & Schulman Inc. is a broker-dealer registered with the Securities and Exchange Commission. The other three firms are unregistered and exempt from SEC regulation -- although, like all companies that sell securities, they are subject to the antifraud and certain other provisions of the securities laws.

Three of the four Bevill, Bresler companies are owned by five individuals, although Robert L. Bevill and Gilbert C. Schulman own 65 percent of each. A fourth firm, Bevill, Bresler & Schulman Government Securities Inc., is wholly onwed by Bevill and Schulman and trades privately. The SEC, in its filing before Newark federal court, alleged that the private trading firm borrowed heavily from Asset Management Corp. to cover losses. In the bankruptcy filing, Asset Management Corp. listed as an asset a $65 million loan due from an unnamed affiliate, which goverment sources said is the private trading company.

According to federal sources, many of Asset Management Corp.'s customers thought they were dealing with the SEC-registered broker and only after the bankruptcy filings did they discover they were dealing with Bevill, Bresler & Schulman Asset Management Corp., not Bevill, Bresler & Schulman Inc.

The failure of E.S.M. and the bankruptcy filing of Bevill, Bresler have renewed congressional calls for regulation of the government securities markets, where hundreds of billions of dollars change hands every day, mainly in complex transactions called repurchase agreements and reverse repurchase agreements.

Government securities dealers often stand as middlemen between organizations with cash to invest and organizations with securities that need cash. The organizations with cash to invest, such as the Army Fund, take securities as collateral in return for the loan to the dealer; organizations in need of cash, such as savings and loans, provide securities as collateral to the dealer in return for loans.

The Army Fund stands to lose money because it left the securities with the dealer rather than demanding control. The savings and loans stand to lose because the value of the securities they provided as collateral exceeded the amount of the loan.