A top name in mobile apps just landed at the top of the hedge fund world. David Einhorn, manager of Greenlight Capital, has taken a big position in Yelp, the hedge fund manager disclosed in a note to investors reported by Yahoo Finance.

The investment reflects a bet that Yelp will emerge unscathed following the release of a new documentary, “Billion Dollar Bully,” that purports to have uncovered “allegations against Yelp regarding extortion, review manipulation and review fabrication” that have led to a series of unsuccessful lawsuits.

“The stock has suffered due to missed expectations and anxiety about an upcoming negative documentary,” Einhorn wrote. “We’ve reviewed the criticisms raised in the trailer to the documentary, and we are comfortable that they won’t have a negative impact on our investment thesis.”

In Einhorn’s eyes, Yelp’s decline over the past year — which some have attributed partly to news of the film’s production — is divorced from the popular app’s fundamentals. “Yelp is a dominant search-and-review website for local businesses, with roughly 200 million unique monthly visitors and the 21st-most popular mobile app in the U.S.,” Einhorn wrote.

With initiatives to boost earnings from reservation and delivery services while cutting staffing costs, Einhorn said, Yelp could double its total revenue by 2019. In the hedge funder’s estimation, that would value Yelp’s stock at $55 a share. The stock closed Monday at $21.54.

As Einhorn is coming off a difficult year that saw Greenlight plunge 20 percent, investors are watching the otherwise successful money manager’s moves closely. This investment is no exception. Following news of Einhorn’s position, shares of Yelp jumped 4.3 percent after-market to $22.46.