Warren Buffett rarely criticizes Kraft Heinz publicly.

Warren Buffett expressed disappointment in Kraft Heinz's decision to split into two companies - a move that essentially reverses his 2015 effort to push for the merger that ultimately became one of his biggest investment mistakes. On Tuesday, Buffett mentioned in a private call with the Financial Times that he was also disappointed that the split did not require a shareholder vote. Berkshire Hathaway currently holds a 27.5% stake in Kraft Heinz, valued at about $8.9 billion, making it the food giant's largest shareholder. Buffett stated that before Kraft Heinz made its final decision, Berkshire Hathaway's CEO successor Greg Abel had directly expressed opposition to the Kraft Heinz management team.