Bill Ackman's Pershing Square just disclosed a 9.9 percent stake in Chipotle Mexican Grill, a stock that has dropped 42 percent in the past year.
The investment comes amid a dismal run for Ackman's holdings. Pershing had lost 14.3 percent this year as of Aug. 31, weighed down partly by a Valeant Pharmaceuticals stake and Herbalife short.
Pershing Square cited those positions as laggards in its interim financial report in June. Valeant shares have plunged more than 70 percent this year, while Herbalife's stock has climbed about 17 percent.
Still, Pershing's performance has improved lately. It saw monthly returns of 2.7 percent and 5.8 percent in July and August, respectively.
Chipotle shares have gained slightly more than 3 percent in the last month. In the same period, some of Pershing's better performing holdings like Air Products & Chemicals and Restaurant Brands International have gained more than 5 percent and 3 percent, respectively.