The suit filed Thursday alleges that they defrauded the county and mishandled investments.
The suit, filed in San Bernardino County Superior Court, claims that Salomon bribed county officials in exchange for county business in the mid-1990s.
The county paid unnecessary commissions to Salomon for some mutual fund purchases, said Dick Larsen, the county's treasurer-tax collector. The county alleges breach of fiduciary responsibility, bribery and fraud.
The suit claims that former county officials directed securities transactions to Salomon and broker Peter Morrison, in the company's Newport Beach, Calif., office.
In exchange, the officials received "kickbacks" including paid trips to Costa Rica and Greece and other entertainment, the suit alleges.
Mr. Morrison and officials at Salomon Smith Barney in New York couldn't immediately be reached to comment.