On June 17, 2016, the Centers for Medicare and Medicaid Services began requiring consumers to document eligibility for special enrollment periods (SEPs). Some evidence suggests the need for verification, but requesting documentation is likely to reduce enrollment by eligible people, given past experience with similar policies. It may be more effective to seek consumer documentation only if the Marketplace cannot quickly verify eligibility with existing data systems or phone calls. Roughly 5 percent of the SEP-eligible uninsured enrolled in 2015. Vigorous marketing by carriers and brokers might greatly increase SEP participation. However, such marketing will not happen if insurers continue seeing SEP members as financially untenable.