Parcel-delivery and technology provider Pitney Bowes Inc. said Monday that President and CEO Marc S. Lautenbach, who had been pressured by a large investor to step down from both roles, has done so, effective immediately.

Jason Dies, who most recently served as the company’s executive vice president and group president, was named interim CEO, Pitney Bowes said, adding that a search is underway for a permanent successor.

Dies has been with the Stamford, Connecticut-based company (NYSE: PBI) since 2015.

Lautenbach, who also resigned his seat on the company’s board, was at the center of a bitter proxy fight involving Hestia Capital Management, which owns more than 9% of Pitney Bowes. Hestia had repeatedly agitated for Lautenbach’s ouster, saying he was responsible for the company’s sagging marketplace and share price fortunes. Lautenbach had been at the helm of Pitney Bowes since 2012.

In May, Pitney Bowes shareholders voted to approve four of the board candidates that Hestia had proposed. The investment firm had initially sought five new board members.