'Too soon' for Chipotle comeback despite Ackman stake, Barron's says Despite activist investor Bill Ackman's Pershing Square reporting a nearly 10% stake in Chipotle, it is "far too soon" to have any real confidence in a comeback for the burrito chain, Johanna Bennett contends in a Barron's article. Bennett notes that short sellers will likely cover positions and fundamentals at Chipotle still face "severe" headwinds that put hopes for a recovery in 2017 in doubt