NEW YORK (AP) — CBS and its majority shareholder are duking it out in a Delaware court.

CBS has sued its majority shareholder, National Amusements, ahead of a board vote on a dividend that would shrink National Amusement's stock ownership from 79 percent to 17 percent, effectively giving CBS independence.

National Amusements said Wednesday it has rewritten CBS' bylaws to require a "supermajority" for a dividend to pass. A hearing is taking place in Delaware Chancery Court in Wilmington, Delaware, on Wednesday.

CBS and Viacom are both controlled by National Amusements, which has been pushing for the companies to combine. CBS, helmed by Les Moonves, has said it is not in the company's best interest to combine with Viacom.