Enrollment through an exchange is controlled by enrollment periods; annual open enrollment to permit yearly enrollment as the name suggests, and special enrollment to handle changes that occur to citizens. Annual enrollment periods ensure that individuals and their families don't wait until they get sick to enroll in coverage, or switch to more comprehensive coverage when in need of an expensive medical procedure. Prior to annual open enrollment, exchanges must provide a written annual open enrollment notification to each enrollee. Legislation defines this must be issued in advance of any period, in the month of September; this allows plan carriers to have made any adjustments to the plans they wish to make available on the exchange, and gives sufficient notice to enrollees to address their options for the upcoming coverage year.
For coverage in the first year, 2014, the ACA has defined an extended initial annual enrollment period between October 1, 2013 and March 31, 2014 where qualified individuals can enroll in a QHP through the exchange. For subsequent coverage in years 2015 and beyond the annual open enrollment period for the individual exchange begins on October 15th and ends on December 7th. During this period, individuals and families already enrolled on a QHP can re-visit the exchange, redetermine their eligibility and entitlement for the different insurance affordability programs, view details of all the plans available to them in the exchange and change coverage from their existing plan to a new one if they so choose.
Any plan selections made during the open enrollment period take effect on January 1st of the following year. Enrollees can change their plan as often as they like within the open enrollment period. That selection is considered 'final' once the open enrollment period has elapsed. If a person chooses not to change their plan during an open enrollment period, then the coverage automatically carries over for another year on their existing plan.
Enrollees who qualify for a special enrollment period are allowed to change plans at any time during their coverage year, as long as they select a new plan within 60 days of the event that triggered qualification. In general, if a client selects a new plan between the 1st and 15th day of any month in a special enrollment period, the effective date of coverage of the plan must be the first day of the first following month. If they select a plan between the 16th and the last day of a month the effective date of coverage must be the first day of the second following month. There are exceptions to this rule, for example, in the case of birth or adoption the exchange must ensure coverage is effective on the date of birth or date of adoption.
Note that the dates from which an enrollee is covered are slightly different for the initial annual enrollment period. Up to and including December 15 2013, any enrollment behaves exactly the same as during a normal annual enrollment period, except that none of the qualified individuals will already be enrolled on a QHP on the exchange; coverage takes effect on January 1, 2014. For the remainder of the initial open enrollment (i.e. December 16, 2013 to March 31, 2014) this period behaves the same as special enrollment periods in terms of plan selection and effective dates; coverage from the first of the first following month when enrolled in first half of the month, and coverage from the first of the second following month when enrollment occurs in the latter half of the month. The qualification for being able to select a plan in this period would be based on whether you have selected a plan already. If you have not already selected a plan, you can select one during this period without any qualifying event – if you have already enrolled on a plan, then you need to qualify for special enrollment.
The dates prescribed are flexible - states may implement coverage dates earlier than those specified if they can prove to HHS that all of the carriers participating in their exchange agree to the shorter timeframes.