Citigroup shareholders sounded a bit like Occupy Wall Street yesterday when they rejected a pay package for its chief executive, Vikram S. Pandit, who was set to receive $15 million. “C.E.O.’s deserve good pay but there’s good pay and there’s obscene pay,” said a principal at a money-management company that voted against the package. About 55 percent of shareholders voted against the plan. The vote is nonbinding, part of the Dodd-Frank financial reform that requires public companies let shareholders voice their opinion about compensation, but Citigroup’s chairman says he takes the vote seriously. Last year Pandit got $1.67 million in salary, a $5.3 million cash bonus, and a retention package valued at $40 million.