Chipotle Mexican Grill Inc. has a new top shareholder after billionaire investor Bill Ackman sold a stake in the burrito chain valued at about $401 million.

Ackman’s Pershing Square Capital Management cut its Chipotle stake to 7.4 percent, down from its previous position of 10.4 percent. The company’s new top shareholder is Vanguard Group Inc., with a stake of about 9.1 percent as of June 30, according to data compiled by Bloomberg.

Ackman’s hedge fund sold 823,357 shares on Aug. 28 for portfolio management purposes, according to a filing on Thursday. Chipotle’s shares have gained 17 percent since Sept. 6, 2016, when Pershing Square disclosed a position in the company.

The shares have performed especially well this year, gaining about 67 percent. Chipotle’s new chief executive officer, Brian Niccol, who joined from Taco Bell Corp. in March, has embarked a turnaround plan that has revitalized interest in the company.

Ackman has said there is plenty of opportunity at Chipotle under its new CEO. He said in April that he didn’t think the company had had any innovation in a decade and it could drive sales by adding breakfast and desserts and extending hours and installing drive-through windows.

Representatives for Chipotle didn’t immediately respond to a request for comment. A representative for Pershing Square declined to comment.