Open enrollment exists because most US-style group benefits operate on annual contracts between the employer and the carrier. The carrier sets renewal pricing once per year; the employer accepts or renegotiates; the employee then has one window to make decisions that lock in for the next 12 months. Outside of open enrollment, benefit changes typically require a qualifying life event - marriage, divorce, birth or adoption of a child, loss of other coverage, change in employment status, or relocation outside the plan service area.
For HR teams, open enrollment is the busiest time of year outside of year-end performance cycles. Communications must explain plan changes clearly, decision support tools must help employees model the trade-offs between premium and out-of-pocket exposure, deadlines must be enforced or defaulted gracefully, and the elections must be transmitted accurately to dozens of carriers. Failure modes are expensive: employees enrolled in the wrong plan often cannot fix the error until the next open enrollment, sometimes 11 months later.
Key Points: Open Enrollment
- Annual decision window: 2-4 week period when benefits can be changed without a qualifying life event.
- Driven by carrier renewal cycles: Most group benefits operate on annual employer-carrier contracts that renew on a fixed date.
- Decision support is critical: Employees consistently underestimate out-of-pocket exposure; modeling tools materially improve plan selection.
- Default rules matter: Most platforms either roll over the prior year’s elections or default to single-employee no-coverage; the choice has significant employee experience implications.
- Mid-year changes need a QLE: Outside open enrollment, changes require a qualifying life event such as marriage, divorce, birth, or loss of coverage.
How Open Enrollment Works in Treegarden
Open Enrollment in Treegarden
While Treegarden is an ATS rather than a benefits administration platform, candidate-facing offer letters frequently reference benefit eligibility timelines and open enrollment dates. The offer letter module supports custom fields for benefits start date and next-open-enrollment notes so candidates have accurate information from day one.
Related HR Glossary Terms
Frequently Asked Questions About Open Enrollment
Most US employers run open enrollment for 2-4 weeks, with 3 weeks being the most common length. The window must be long enough for employees to receive materials, attend any information sessions, model trade-offs, consult their families, and submit elections - but short enough to maintain urgency and meet the carrier deadlines for confirming next-year enrollment.
Missing open enrollment means the employee’s prior-year elections continue (if the employer’s plan rules permit roll-over) or the employee defaults to no coverage (if the plan requires affirmative annual election). The employee cannot change benefits again until either the next open enrollment or a qualifying life event - which can be 11 months away. This is one of the most common sources of HR ticket volume during the first quarter of the plan year.
A qualifying life event (QLE) is a major personal change that allows benefit elections to be made or changed outside open enrollment. The most common QLEs are marriage, divorce or legal separation, birth or adoption of a child, death of a covered dependent, loss of other health coverage, change in employment status that affects eligibility, and a permanent move outside the plan’s service area. Documentation is typically required and changes must be made within 30-60 days of the event.
Generally no for group health insurance - the employer-carrier contract runs for the full plan year and material plan changes mid-year would invalidate employee elections made during open enrollment. Exceptions exist for carrier insolvency, regulatory changes, or merger and acquisition events. Voluntary supplemental benefits can sometimes be added mid-year as new offerings without disrupting existing elections.