** Restaurant chain operator's shares up 4.67 pt at $574.41 after Boston outbreak mostly linked to norovirus, not E. coli, and CEO's comments
** Boston Public Health Commission says laboratory testing confirm presence of norovirus in at least 80 people who ate at a Chipotle restaurant
** Founder and co-Chief Executive Steve Ells tells NBC's "Today" program that the company is putting in place procedures to make restaurants "safest place to eat"
** "We see value in shares from current levels for investors that can look through the potential near-term choppiness," William Blair analysts write in note
** Short interest was 5.6 pct of the company's shares outstanding as of Nov. 30; stock had moderate chance of short squeeze, with a 52/100 score, according to StarMine data
** Up to Wednesday's close, the stock had fallen about 14 pct since Oct. 31, when the first E. coli outbreak was reported