Chipotle (CMG) often touts themselves as a healthy alternative to the heavy, deep-fried brands that have long dominated the fast food market. Chipotle bolsters this healthy image by being wholly transparent about what goes into their food: they note which ingredients are free range or organic, and clearly label the calorie counts on their ingredients. And the model has treated the company well: Chipotle is up 24.31 percent on the year. But in an unusual move to take that transparency one step further, yesterday the “fast-casual” chain began noting on their menus which ingredients contain GMOs (genetically modified organisms) with a big red “G.” It’s a move without precedent in the major fast food chain market.

GMOs–or food that has been genetically altered to increase yield–are highly contentious in the public consciousness, and Chipotle acknowledges this. After a jokey preamble assuring customers GMOs aren’t proved to cause health problems, Chipotle’s Ingredient Statement reads “Our goal is to eliminate GMOs from Chipotle’s ingredients, and we’re working hard to meet this challenge.” They cite switching from using soybean oil in their fryers to sunflower oil as an example. According to their “Ingredient Statement” (the breakdown of what goes in their burritos, tacos and bowls) over half of their ingredients contain GMOs.

Whether Chipotle’s move pays off in the long-term remains to be seen. But the bold decision to own up to their reliance on GMOs has been welcomed by the market, at least initially. Chipotle’s stock opened the day at $363.62 a share before spiking up to $368.14 at the start of trading, for a two percent increase, before falling back down.

Chipotle, formerly controlled by McDonalds (MCD), went public in 2006 at $22 a share.