Bill Ackman bagged a $100 million profit on a recent Nike trade, sources familiar with his hedge fund told The Post.

The struggling activist investor bought the passive Nike stake — an unusual move for the vocal money manager — during the fourth quarter of 2017. The roughly six-month investment, which his fund exited a few weeks ago, proved to be a quick winner for the fund, gaining roughly 32 percent.

It’s a welcome boost for Ackman, whose $8.4 billion fund Pershing Square Capital is down 5.8 percent through February, following three consecutive years of losses.

Nike is a “high-quality business” with a “dominant market position,” Pershing Square said in an investor presentation earlier this year.

Ackman’s timing appeared to be good, as Nike shares have taken a hit in recent days after two top executives left following complaints of sexual misconduct at the company. One of the exits was brand president Trevor Edwards, who was seen as a likely successor to chief executive Mark Parker.

The shares lost 2.9 percent in regular trading hours on Thursday to close at $64.42.

However, after the Beaverton, Ore., company on Thursday reported better-than-expected fiscal third quarter results Nike shares spiked as much as 7.3 percent in after-hours trading.

News of Ackman’s Nike sale was first reported by the Wall Street Journal.

Reps from Pershing Square declined to comment.