Q: If my coverage ends on December 31st, can I be confident that my new coverage will be in force if I enroll by December 15?
A: Yes. As long as your application is completed by December 15 and you pay your first premium by the due date set by your health insurance carrier, your coverage will be in effect January 1.
There are two states — Massachusetts and Rhode Island — where enrollments can be completed through the state-run exchanges as late as the 23rd of the month and still have coverage effective the first of the following month. So in those states, you can enroll as late as December 23 for a January 1 effective date (Washington state’s exchange used to follow that same schedule, but they switched in 2017 to having a deadline of the 15th of the month for a plan to be effective the first of the following month).
When the exchanges were in their infancy, it was common to see extensions to the December enrollment deadline for a January 1 effective date. In the fifth open enrollment period (for 2018 coverage), this wasn’t as common as it used to be. But there were still six state-run exchanges that allowed people to enroll after December 15, 2017, for coverage effective January 1, 2018.
People whose coverage is being terminated on December 31 can enroll as late as December 31 and have coverage effective January 1, as long as they use the special enrollment period triggered by loss of other coverage.