Kraft Heinz is not in talks to acquire Mondelez International, according to people familiar with the matter. An earlier report that the U.S. snack maker could be a target for the company sent shares higher.

Mondelez rose 4.7 percent at 5:57 p.m. in New York while Kraft Heinz advanced 2.6 percent after Bilanz magazine reported that Kraft Heinz, backed by Warren Buffett's Berkshire Hathaway Inc. and Jorge Paulo Lemann's 3G Capital, is planning a takeover, citing an unidentified source.

A spokesman for Deerfield-based Mondelez declined to comment. Representatives for Kraft Heinz, which is headquarted in Chicago and Pittsburgh, didn't immediately respond to a request for comment.

Berkshire and 3G have been expanding in the food industry. They took ketchup maker H.J. Heinz private in 2013 and then merged it with Kraft Foods Group last year. The combined company has gained in market value as 3G slashed costs by cutting jobs and shutting factories. Mondelez, the maker of Oreo cookies, was previously part of Kraft, and the companies split in 2012.