Tribune Media, one of the largest U.S. television station operators, said on Tuesday that activist investor Starboard Value had taken a 6.6 percent stake in the company.
Tribune's shares were up nearly 2.5 percent at $34.54 in trading after the bell.
Last year, Starboard disclosed a stake in Tronc, the newspaper business that Tribune spun off in 2014.
Higher programming costs and a challenging advertising environment have pushed Tribune to rethink its business strategy.
The company said in November that it was working with its financial advisers on a strategic review of its assets. Tribune had hired investment banks Moelis and Guggenheim Securities as financial advisers early last year.
Tribune sold its media data unit Gracenote to advertising tracking company Nielsen Holdings for $560 million in December. The company could also shed other parts of its business, Reuters had reported.
Starboard, led by Jeffrey Smith, is known for shaking up boards and pushing companies into mergers and acquisitions.