Kraft Heinz shares fell 3.6% in premarket trading Wednesday after a filing revealed that Berkshire Hathaway may sell its 27.5% stake in the food company.

The regulatory filing showed that Warren Buffett’s conglomerate is considering divesting its substantial position in Kraft Heinz, which has been one of Berkshire’s major holdings.

Berkshire Hathaway has maintained its large ownership position in Kraft Heinz since the 2015 merger that created the combined food giant. The potential sale would represent a significant shift in Berkshire’s investment portfolio.

The market reacted to this news with the premarket decline, as investors assessed the implications of Berkshire potentially exiting its position in the food manufacturer.