Hilton Hotels Corp., the seventh-largest hotel company in the U.S., was sued by a former employee who claims the company gives many salaried and nonunion workers smaller pensions than federal law entitles them to. Jamal Kifafi, who worked for 10 years at the Capital Hilton in Washington, said in court papers that Hilton employees earn pension benefits unevenly, with new workers acquiring benefits at a lower rate than workers who have longer service. If the lawsuit is successful, Hilton could be liable for more than $50 million in additional benefits, said Stephen Bruce, Kifafi's attorney. He said more than 10,000 workers might be affected. Kifafi is seeking class-action status for the suit, filed in federal court in Washington. A Hilton spokesman said it is company policy not to comment on pending litigation. Beverly Hills-based Hilton's shares rose 50 cents to close at $31.56 on the NYSE.