LAS VEGAS, May 18 (Reuters) - Billionaire investor William Ackman, who invested with casual dining company Chipotle Mexican Grill Inc last year, said on Thursday that the company's Chief Executive Officer Steve Ells is "outstanding."

Speaking at the annual SkyBridge Capital conference in Las Vegas, Ackman also said that hedge funds should deliver high returns or cut their fees. "Hedge funds should be a place where you earn high returns or compromise on fees," he said.

Hedge fund returns have been lagging for years and investors have complained about their high fees.

(Reporting by Svea Herbst-Bayliss; Editing by Lisa Shumaker)