Shari Redstone Moves to Defend Family’s Voting Power Over CBS

Amendment would require supermajority to approve certain actions, likely blocking dilution to family’s voting control

Keach Hagey and

Joe Flint

Updated May 16, 2018 2:28 p.m. ET

Shari Redstone is moving to thwart CBS Corp.’s efforts to strip her family of voting control.

The Redstones’ family holding company, National Amusements Inc., issued a change to CBS’s bylaws on Wednesday in an attempt to block the board’s ability to dilute its voting power.

Amending the bylaws marks a significant escalation in the battle...