The burrito chain debuts on the Top 50 while expanding at a breakneck pace, adding 192 restaurants last year and pulling in $4.11 billion in revenue, a 27.8% increase since 2013. The stock price has risen more than 22% in the past twelve months, to over $670 per share. With more than 200 restaurant openings on the horizon for 2015, it has no plans to slow down. The company also faced a major hurdle when it had to take pork off the menu of 500 of its 1,700 stores in January because, it says, suppliers weren’t meeting its animal welfare standards.