A number the Marketplace provides when you qualify for a health insurance exemption. When you fill out an exemption application, the Marketplace will review it and determine if you qualify. The Marketplace will mail you a notice of the exemption eligibility result. If you qualify for an exemption, the notice will include your unique identifier, called the exemption certificate number (ECN). Each member of your household who qualifies for the exemption will get their own ECN. You’ll need your ECN when you file your federal taxes for the year you don’t have coverage.
Use these numbers to complete IRS Form 8965 — Health Coverage Exemptions (PDF, 73 KB).
If you qualify for a health coverage exemption, you don’t have to pay the fee for the months you didn’t have health coverage.
The fee is a payment ("penalty," "fine," "individual mandate") you make when you file federal taxes if you didn't have health insurance that counted as qualifying health coverage. The fee for not having health insurance no longer applies. This means you no longer pay a tax penalty for not having health coverage.
If you need exemption information, you can find more information on how to apply for an exemption through healthcare.gov