Two years after a string of food safety incidents battered sales and scared away diners, Chipotle Mexican Grill still isn't on solid ground.
While the beleaguered burrito chain has returned to profitability and its same-store sales have begun trending in a positive direction, its successes have been overshadowed by a data breach, overtime pay lawsuits and drug charges being brought against a senior manager.
"While these things do not deter customers as much as a food poisoning outbreak, they do raise questions about how well the company is managed and suggest a lackadaisical approach," Neil Saunders, managing director of GlobalData, told CNBC via email.
In the hope of luring back lapsed customers, Chipotle continues to invest heavily in marketing and promotions. In an SEC filing last month, the chain said that it would be increasing its spending in these areas, saying expenses would rise as much as 0.3 percent as a result.
It began a new ad campaign in April, which includes national TV commercials. Using the tagline "As real as it gets," the campaign focuses on the quality of Chipotle's ingredients.
Despite these investments, Chipotle's most loyal customers still aren't returning as frequently as they did before the outbreaks, and new customers are skeptical about the brand.
A report by M Science found that the transaction frequency of the top 20 percent of Chipotle's most loyal customers dropped off significantly in the last quarter of 2015 and has yet to return to its pre-outbreak levels.