The Obama administration is promising to crack down on healthcare customers who buy coverage in between enrollment periods to lower costs. Andy Slavitt, acting head of the Centers for Medicare & Medicaid Services, acknowledged publicly for the first time Monday night that some customers are using loopholes in the enrollment sign-up periods to avoid paying healthcare premiums year-round.

He said more details about the administration’s plans will come next week, after the Jan. 31 deadline for coverage.