Supplementary Coverage

Updated: 20 April 2026

What Does Supplementary Coverage Mean?

Supplementary coverage refers to additional insurance that a policyholder can purchase to complement their primary insurance plan. It helps cover expenses not included in the regular plan, such as lost wages or medical costs.

Insuranceopedia Explains Supplementary Coverage

Regular insurance policies often do not cover certain services or out-of-pocket expenses, which is where supplementary coverage comes into play. Some of these policies reimburse deductibles, copayments, and coinsurance, while others provide a cash benefit that the policyholder receives either as a lump sum or over a specified period. Knowing how those three cost-sharing pieces work on your base plan is what tells you whether supplementary coverage is worth the extra premium, and our guide to premiums, deductibles, co-pays, and coinsurance walks through each one.

A common example is Medigap, a supplementary coverage plan for individuals enrolled in Medicare. Since Medicare does not cover all health-related services and medical supplies, Medigap helps fill in these gaps, as the name suggests. Critical illness insurance is another common example in this category, paying a lump-sum cash benefit if you’re diagnosed with a covered condition like cancer or a heart attack.