NEW YORK, NOV. 29 -- Two New York men alleged to be bookmakers and a former clerk at Salomon Brothers Inc. have been charged with being members of a major international gang that peddled stolen stocks and bonds, including securities that were taken at knifepoint in a record $550 million robbery in London in May.

The three were among 12 men indicted by a federal grand jury in Manhattan on Nov. 9 for conspiracy to distribute purloined U.S. and British securities. The indictment was unsealed and made public today.

The charges were the fruit of an 18-month FBI investigation, which was hampered by the gangland-style slaying in Houston in August of an alleged member of the ring who was cooperating with the authorities at the time.

The investigation began with inquiries into the theft of $7 million in securities from Salomon Brothers, a leading New York investment bank, in the spring of 1989.

Later, some of those charged with distributing the securities stolen from Salomon Brothers were also alleged to have conspired to sell Bank of England securities stolen from a money-broker's courier on May 2 in the biggest robbery ever in the London financial district.

The defendants face prison terms of five to 60 years and fines of up to $1.2 million on charges of transporting stolen property, aiding racketeering, extortion, money laundering, conspiracy and other crimes. Five of the 12 are still at large.

According to the indictment, former Salomon Brothers clerk Anthony J. Lama stole $7 million in securities to repay a gambling debt after the two alleged bookmakers, Robert R. Rosenfeld and Ted R. Ballison, threatened to kill him.

Lama, 36, of Staten Island, worked as a clerk in an office that processed securities transactions, until he was dismissed after the theft came to light. He was expected to turn himself in to authorities at his arraignment next Thursday and apparently is cooperating with prosecutors.

The securities stolen from Salomon Brothers included bonds of the A&W Brands Holding Co. and notes of the New York Job Development Authority, the European Investment Bank and General Motors Acceptance Corp.

Sources said that most of the stolen securities had been recovered and that, in any case, Salomon Brothers was insured against their loss. Salomon Brothers declined to comment.

The alleged bookmakers, Rosenfeld, 46, of Woodbury, N.Y., and Ballison, 44, of Brooklyn, were arrested six days ago. They are being held without bail at the Metropolitan Correction Center here.

In addition to his alleged involvement in peddling the Salomon Brothers securities, Rosenfeld was charged with having attempted last July 31 to sell about $19 million of the stolen Bank of England securities to an undercover FBI agent posing as a narcotics dealer.

The indictment also charged W. Keith Cheeseman and Raymond Ketteridge with conspiring to sell the English securities, which included certificates of deposit and Treasury bills. Both defendants are in jail in Britain and are alleged by authorities there to be leading criminal figures.

The other defendants charged in the indictment were accused of playing various roles in selling or conspiring to sell the Salomon Brothers or British securities in Texas, Britain, the Netherlands, Belgium and Switzerland.

The investigation was clouded by the murder of John Mark Lee Osborne, who was found shot twice through the head in the back seat of a car in Houston in August. He was killed three weeks after he and Rosenfeld tried to sell stolen securities to the FBI agent.