Warren Buffett's Berkshire Hathaway has lost almost $5 billion this year on its investment in Kraft Heinz as the packaged food company's stock has continued to tumble.

Shares of Kraft Heinz hit a record low Thursday, falling more than 14% at one point, after the company announced an additional write-down of $1.22 billion and missed revenue expectations.

Kraft earned 37 cents per share, or 78 cents per share excluding the writedown, and generated $6.406 billion in revenue during its fiscal second quarter. Analysts expected earnings of 75 cents per share and $6.580 billion in revenue, according to Refinitiv.

The stock closed down 8.58% on Thursday.

Berkshire Hathaway owns more than 325 million shares of Kraft Heinz, representing 26.7% of the company. The value of the position has declined to about $9.19 billion from just over $14 billion since the start of the year, creating a roughly 34% loss for Berkshire Hathaway.

Kraft Heinz was the sixth-largest holding in Berkshire's portfolio as of the end of 2018. Berkshire Hathaway and 3G Capital bought Heinz in 2013 for $23 billion and merged the company with Kraft two years later.

"I made a mistake in the Kraft purchase in terms of paying too much," Buffett told CNBC in June.