Why do I have to provide my Social Security number to enroll in health insurance through the exchange?

If you’re not lawfully present in the U.S., you cannot enroll in coverage through the marketplace. (Note that Washington state has received federal approval to begin allowing undocumented immigrants to enroll through its state-run exchange in 2024, albeit without any federal subsidies. And Colorado has established a separate portal where undocumented immigrants can enroll in state-subsidized coverage.) The marketplace uses applicants’ SSNs to confirm that they are lawfully present residents. So you’ll need to provide SSNs for all household members who are applying for coverage, regardless of whether you’re applying for financial assistance.

If you’re applying for financial assistance – which the vast majority of marketplace enrollees are eligible to receive – you’ll need to provide SSNs for all members of the household who are listed on the household’s tax return, regardless of whether they’re applying for coverage. This is so that the marketplace can confirm the household’s total income, which is used to determine eligibility for premium subsidies and cost-sharing reductions.

If you fail to provide your SSN, it can trigger a data matching issue (DMI), which means the marketplace will reach out to you to get more information. It’s also important to keep in mind that the names you provide to the marketplace should match the names on file with the Social Security Administration. If they aren’t the same, that could result in a DMI, despite the fact that you provided the correct SSN. So if you’ve changed your name recently, you’ll want to make sure you’ve updated the records on file with the Social Security Administration.

Even if you take the DIY approach and enroll without assistance, there are employees and contractors at the exchange who will need to have access to the data in your application, including your SSN. But all of these people – including brokers, Navigators, and people who work at the exchange – have received training on how to safeguard applicants’ personal information, and are bound by rules that require them to do so.

As is always the case with important personal information, you’ll want to do your due diligence before providing any details. As a general rule, don’t give your SSN (or any other private information) to someone who cold calls you. Before working with an agent or broker, you should confirm that they are licensed by the insurance department in your state, and certified to work with the exchange. Navigators are not licensed by state insurance departments, but they are certified by the exchange.

Here’s insurance department contact information for every state, and here’s a tool where you can find brokers and enrollment assisters who are certified to work with the federally-run exchange, which is used in 33 states. The remaining states run their own exchanges, and they have similar tools that you can use to ensure that a broker or enrollment assister is certified by the exchange.

If you don’t provide your SSN on your application and you get a follow-up call from the marketplace, here’s what to know about protecting your personal information and avoiding fraud.

Louise Norris is an individual health insurance broker who has been writing about health insurance and health reform since 2006. She has written dozens of opinions and educational pieces about the Affordable Care Act for healthinsurance.org.