PepsiCo shares popped Tuesday after the Wall Street Journal reported Elliott Investment Management has taken a significant stake to become the consumer giant’s top five active investors excluding index funds.

Shares of PepsiCo climbed 4.5% in premarket trading. The stock is down about 2% this year, significantly lagging the broader market.

The Paul Singer-founded Elliott’s bet in Pepsi is worth about $4 billion, the Journal reported, citing people familiar with the matter. Elliott’s plan to push for changes at Pepsi is unclear at this time, the Journal said.

Elliott didn’t immediately respond to CNBC’s request for comment.

Pepsi has been cutting costs and trying to improve its profit margins. The company closed two manufacturing plants for its North American food business during the quarter. Pepsi said it is trying to make its transportation and logistics more efficient. The company is also evaluating how it spends its marketing dollars to make sure it is getting the best return on its investment.

In July, Pepsi reported quarterly earnings and revenue that topped analysts’ expectations, as the company projected that weak North American demand will rebound as strategy changes take hold.

Elliott has a history of activism that has at times yielded strong returns for investors. It’s a large holder of Phillips 66 and Southwest Airlines and has been driving changes at those two companies.

— Click here to read the original WSJ story.