About 14.6 million Medicare fee-for Service beneficiaries have supplemental MediGap coverage. Medigap plans are standardized benefit plans s designed to cover cost-sharing gaps under original Medicare, such as deductibles, coinsurance, and copayments. Other sources of coverage that Medicare beneficiaries may have include retiree coverage through a former employer, group health care coverage through a current employer https://sgp.fas.org/crs/misc/R47552.pdf