CBS said in a statement Wednesday: "The industry and the marketplace know Leslie Moonves' record and we think it speaks for itself." Viacom declined to comment. Thanks to the dual-class stock structure — something CBS and Viacom share with the likes of Facebook, Alphabet and The New York Times Company — there's little that regular shareholders, or management of either company, can do. Legal experts say that National Amusements has fiduciary duties to shareholders of each company, but that the Redstones unquestionably have the power to replace board members. "You can stack the board," said John Coffee of Columbia Law School, though he added that "it might be poor form to stuff the board" before pushing through a merger or C.E.O. change. Charles Elson, director of the John L. Weinberg Center for Corporate Governance at the University of Delaware, said that companies controlled by a dual-class structure can sometimes opt for other shareholders to have a voice. But that isn't a requirement.