Chipotle Mexican Grill (CMG) shares fell Tuesday on news that the burrito giant will replace much of the leadership that helped propel its stock price to guac-defying levels.

The stock fell about 11% in morning trading after Starbucks (SBUX) announced that Chipotle CEO Brian Niccol would become the company’s CEO and chairman of the board starting in September. The news delays the retirement of longtime CFO Jack Hartung, who was scheduled to retire in January. While he will be replaced by Adam Rymer in January, he will now stay on indefinitely in another role to assist with the transition.

This morning’s drop in Chipotle stock comes after shares rose dramatically during Niccol’s tenure; they are not far from the record highs reached earlier this year.

Chipotle COO Scott Boatwright will serve as interim CEO, while board member Scott Maw has been named chairman. “We are well prepared for events like this because we have a large number of people within the organization,” Maw said.

Starbucks said it expects Niccol to be a “transformative” leader and credits him with having that impact at Chipotle. He joined from Taco Bell in 2018, a company plagued by food safety issues that damaged its brand. While the company is not immune to criticism—it has recently had to contend with the perception that it skimps on portions, for example—Niccol has helped it modernize operations while making targeted menu updates.

Restaurant chains want to emphasize the added value for price-conscious consumers

The company also has to contend with a restaurant atmosphere in which fast-food chains emphasize quality and consumers feel overwhelmed.

Chipotle shares, which rose slightly yesterday, had risen more than 20% this year and 50% over the past 12 months through Monday’s close. The company split its shares 1-for-50 in late June and last month reported second-quarter results that beat Wall Street’s expectations for revenue and profit.

Even before today’s news broke, Wall Street was broadly optimistic about Chipotle: According to Visible Alpha, nearly all analysts covering the stock recommended buying the stock, with the average price target about 17 percent above Monday’s closing price.

UPDATE – This story has been updated to reflect new share price information.