The San Francisco-based investment firm, which owns a 4.4% stake in the convenience store operator, is ratcheting up the pressure by saying publicly that Isaka has acted in bad faith since becoming president in 2016.

"It is time to find a new President for Seven & i," ValueAct wrote to Seven & i shareholders in a letter dated April 20. The letter also criticizes the board for having failed to conduct a succession review for Isaka.

ValueAct said Seven & i recorded meetings with its team without its consent, violating privacy laws around the world. Then it leaked audio from a March 15 meeting to a news outlet, the investment firm said.

Seven & i did not immediately respond to a request for comment and ValueAct declined to comment beyond the contents of the letter.

(Reporting by Svea Herbst-Bayliss; Editing by Edmund Klamann)

By Svea Herbst-Bayliss