Kraft Heinz’s quarterly profit and sales missed analysts’ estimates on Friday, hurt by lower shipments for nuts, natural cheese and cold cuts in the US.

Shares of the company, which is backed by billionaire investor Warren Buffett and private equity firm 3G Capital, fell 6 percent in early trading.

Sales in the US, the company’s biggest market, fell 1.1 percent, to $4.79 billion, declining for the seventh straight quarter and also missing analysts’ average estimate of $4.81 billion, according to Thomson Reuters I/B/E/S.

The company’s net income rose to $8 billion, or $6.52 per share, in the fourth quarter ended Dec. 30, from $944 million, or 77 cents per share, a year earlier.

The reported quarter had a benefit related to the recent overhaul of the tax code.

The company, which owns brands such as Velveeta cheese and Heinz ketchup, said net sales inched up 0.3 percent, to $6.88 billion, missing estimates of $6.92 billion.

Excluding items, the company earned 90 cents per share, missing estimates of 95 cents.