The CEO of UnitedHealth, the nation’s largest health insurer, said on Tuesday he regretted the decision to enter the ObamaCare marketplace last year, which the company says has resulted in millions of dollars in losses. “It was for us a bad decision,” CEO Stephen Hemsley said at an investor’s meeting in New York, according to Bloomberg Business. UnitedHealth announced last month that it would no longer advertise its ObamaCare plans over the next year and may pull out of the exchanges completely in 2016.