New York CNN Business  — 

Chipotle dealt with a major health crisis that could have led to permanent damage to the restaurant chain’s reputation and stock price.

But customers have clearly forgiven (and perhaps forgotten) about the E. coli outbreak of late 2015 and early 2016. So has Wall Street.

Shares of Chipotle (CMG) have soared nearly 55% this year, making it the fourth-best performer in the S&P 500.

The stock did tumble Thursday after an analyst at BMO Securities cited concerns about African swine fever in China leading to higher pork prices that could hurt profits.

But Chipotle told CNN Business the worries were overdone and that the company did not expect a significant impact from the swine fever outbreak. Shares rebounded Friday.

This year’s stock pop also follows a 57% gain last year. Chipotle has done so well that it’s now trading at about $667 – just 12% below the all-time high of about $759 that it hit in August 2015 just before the E. coli outbreak.

New food and bigger emphasis on digital

It’s a testament to the changes Chipotle made to shake up its menu and embrace digital ordering since Brian Niccol, the former head of Yum Brands (YUM)-owned Taco Bell, took over the company in early 2018.

Since then, Chipotle has added new salad bowls to cater to consumers on paleo and ketogenic diets and has also introduced more menu options for vegetarians and vegans.

Chipotle’s first-quarter results clearly show the company’s woes are now a thing of the past. Total revenue surged 13.9% and sales at restaurants open at least a year were up nearly 10%. Digital sales more than doubled and now account for about 16% of total revenue.

“We are definitely under a digital transformation at Chipotle,” Niccol told CNN’s Christine Romans in February.

Ackman loves Chipotle

Even hedge fund manager Bill Ackman, an activist who has gotten a lot of attention for betting against Herbalife (HLF), likes the stock.

Ackman’s Pershing Square Capital Management is the second-largest investor in Chipotle, with a 6.7% stake. Only mutual fund giant Vanguard owns more of Chipotle. It has a 10.6% stake.

Ackman wrote in his first quarter shareholder letter that the latest Chipotle results “continued to demonstrate the significant progress that CEO Brian Niccol and his team have made in dramatically improving performance and positioning the company for long-term sustainable growth.”

He added that “we believe that Chipotle is in the early innings of its transformation” and that its “world-class management team should drive superlative growth in sales and profits for years to come.”

Many Wall Street analysts also believe the momentum will continue. Overall sales are expected to increase more than 10% this year and 2020 while earnings are projected to rise at a nearly 30% clip, on average, for the next five years.

What’s more, eight analysts now have a price target on Chipotle that’s higher than the all-time high it hit in 2015, including one analyst who believes the stock could hit $820 – nearly 25% above current levels.