BUSINESS DIGEST
Companies A remarkable week in American corporate history ended with an about-face by American Express's chairman, who resigned just days after winning a board room battle. The turmoil at American Express, along with significant shifts at I.B.M., Westinghouse and Sears, signaled a shift in which shareholders are gaining more leverage over executives. [ Page A1. ] As Harvey Golub assumes the chief executive's job today at Amerian Express, he inherits several critical cases from James D. Robinson 3d. [ D1. ] Revlon's No. 2 executive is expected to step down. Insiders say Michael Hammond will be succeeded by George Fellows, a senior executive at Colgate-Palmolive. [ D1. ]