Warren Buffett's company reported less than half as much profit in the second quarter as it took a $3.76 billion writedown on the value of its stake in Kraft Heinz as that iconic food producer considers largely undoing the merger that Berkshire Hathaway helped bankroll.

Warren Buffett's Berkshire Hathaway said on Saturday it took a $3.76 billion write-down on its stake in Kraft Heinz during the second quarter, an acknowledgment the decade-old investment hasn't worked out.

Berkshire Hathaway ( NYSE: BRK.A ) ( NYSE: BRK.B) on Saturday posted a nearly 4% decline in quarterly operating profit, hurt by soft insurance underwriting earnings and a $3.8B hit to its stake in ketchup giant Kraft Heinz ( KHC ).