Federal Data Services Hub: How It Verifies Your Eligibility

The Federal Data Services Hub is a routing system the Centers for Medicare & Medicaid Services (CMS) built to check Health Insurance Marketplace applications against existing federal and state records in real time. It does not store your information. It sends narrow queries to the agencies that already hold the authoritative records, receives the answers, and hands them back to the Marketplace so an eligibility decision can happen within minutes.¹

What the Hub Actually Does

Think of the Hub as a digital middleman. When you submit a Marketplace application, it asks each relevant federal database a specific question, gets a specific answer, and passes that answer back to the Marketplace’s eligibility engine. There is no central pool of consumer records inside the Hub itself. CMS designed it that way on purpose: with nothing retained, a single breach cannot expose a large pile of sensitive data.¹

Each verification is a standalone transaction. The Hub pulls only the data points needed for a specific eligibility question. Marketplace workers do not get to browse your tax return or your immigration file. CMS calls it a single interface point through which parties may exchange data, built to federal security and data transport standards.²

What It Checks and Where the Data Comes From

The Hub confirms several categories of information, each from the agency that owns the authoritative record. Together they decide whether you qualify for a Marketplace plan, for advance premium tax credits, for cost-sharing reductions, or for Medicaid or the Children’s Health Insurance Program.

Identity and Social Security Number

Your Social Security number goes to the Social Security Administration, which authenticates your identity and checks death records.³

Income

Your household income sets the size of any premium tax credit. The Hub pulls prior-year tax return data from the IRS so the Marketplace can compare what you put on your application to what you filed.¹ Tax records can be a year or more old, so CMS also contracts with Equifax Workforce Solutions and its payroll database, The Work Number, for more current employment and income data supplied directly by employers.⁴

Citizenship and Immigration Status

You must be lawfully present in the United States to enroll in a Marketplace plan. The Hub checks status through the Department of Homeland Security’s Systematic Alien Verification for Entitlements (SAVE) program, run by U.S. Citizenship and Immigration Services.⁵ If the electronic check cannot confirm status right away, you stay enrolled while you send in documents.⁶

Incarceration

People currently incarcerated cannot buy a Marketplace plan, because the correctional facility provides health care during that time and federal subsidies are not available. The Hub confirms incarceration status against government records.⁷

Existing Coverage

Comprehensive coverage through certain public programs disqualifies you from Marketplace subsidies. CMS has security and privacy agreements with the Department of Veterans Affairs, Medicare, TRICARE, the Peace Corps, and the Office of Personnel Management to check for existing enrollment.¹ OPM, for instance, shares Federal Employees Health Benefits Program data so the Marketplace can see whether a federal worker already carries qualifying insurance.⁸

Employer-Sponsored Coverage

If your employer offers a plan that meets the Affordable Care Act’s minimum value and affordability standards, you generally cannot get premium tax credits for a Marketplace plan instead. For 2026, coverage counts as affordable if your share of the premium for the lowest-cost self-only plan is 9.96% of household income or less. If the employer plan fails either test, Marketplace subsidies remain on the table.⁹

One category sits outside the Hub. Tribal membership, which unlocks special cost-sharing protections for American Indians and Alaska Natives enrolled in federally recognized tribes, is not verified electronically. You send in a document such as a tribal identification card or Certificate of Indian Blood within 90 days of your eligibility notice.

When the Hub Can’t Confirm Something

Sometimes what you enter does not match what the Hub finds. The Marketplace calls this a data matching issue, or DMI. It is not a denial. You stay enrolled and keep any subsidies while you fix it, but the deadline matters.¹⁰

Income mismatches: 150 total days, an initial 90-day window plus an automatic 60-day extension.¹¹
Citizenship or immigration status: 95 days from your eligibility notice.¹⁰
Everything else: 90 days from the eligibility notice.¹⁰

Miss the deadline and the Marketplace redetermines your eligibility using whatever trusted data it has. For income, that can mean losing some or all of your financial assistance. For unresolved citizenship or immigration issues, it means your Marketplace coverage ends.¹¹ A lot of people are hurt by treating the DMI notice as junk mail and losing coverage or subsidies they were actually entitled to.

Which documents you need depends on the mismatch. If your income has stayed roughly the same, your most recent tax return or W-2s usually work. If you started a new job, pay stubs from that job are more useful than paperwork from the old one. If income changed sharply, send documents that show the change, such as pay stubs at the new wage or a letter confirming when contract work ended.¹²

If You Disagree With the Result

You have 90 days from your eligibility notice to request an appeal. Before you file, check whether the Marketplace simply asked for additional documents; sending them in often resolves the problem without a hearing.¹³

Appeals cover a wide range: a finding that you are ineligible for a Marketplace plan, the amount of financial help you were awarded, a denied Special Enrollment Period, or a failure to give you a timely determination. Miss the 90 days and you can still file a late appeal with an explanation; the Marketplace may grant an extension.¹³

Automatic Renewal Each Year

The Hub does not only serve new applicants. Before each open enrollment, the Marketplace runs current enrollees back through it. When you first apply for advance premium tax credits, you are asked for consent to access your IRS tax data for five years. If you agreed, the Marketplace pulls your latest return through the Hub and recalculates your subsidy without you logging in.

For enrollees who do not return to update anything, the Marketplace works through a hierarchy of income sources, starting with the most recent projected or reported income, and adjusts for expected growth using the change in the federal poverty level. The auto-renewed subsidy may not match last year’s. If you did not consent to tax data sharing, you have to return to the Marketplace and update your information to keep subsidies flowing.

Even if auto-renewal keeps your plan active, log in and update your income each year. If your subsidy was based on outdated tax data and your income actually rose, you could owe money when you file your return.

How Your Data Is Protected

The Hub falls under the Federal Information Security Modernization Act of 2014, which sets minimum security standards for federal information systems.² The Privacy Act of 1974 adds more limits: federal agencies cannot disclose records to another agency or person without written consent except in specific statutory circumstances, every disclosure has to be logged, and logs have to be kept for at least five years.¹⁴

Technically, the Hub encrypts data in transit so it cannot be read if intercepted. Access uses multi-factor authentication and role-based permissions, so workers only see what their job function requires. Regular assessments check that the infrastructure meets current federal standards, and audit logs record every query.¹

CMS separates a breach (unauthorized access or disclosure of personally identifiable information) from an incident (an adverse event like a misdirected email with potential exposure). Breaches must be reported to the CMS IT Service Desk within 24 hours of discovery, incidents within 72 hours. If you use a Direct Enrollment or Enhanced Direct Enrollment partner site and suspect your account was accessed without authorization, report it to both the CMS IT Service Desk and the partner site’s help desk, and change your passwords right away.¹⁵

1
Centers for Medicare & Medicaid Services. Security of the Marketplace Data Services Hub
2
CMS Information Security and Privacy Program. Privacy Impact Assessment for the Federal Data Services Hub
3
Social Security Administration. Data Exchange
4
Equifax Inc. Equifax Contract with CMS Renewed, Will Continue Verification for Affordable Care Act Applicants
5
U.S. Citizenship and Immigration Services. SAVE
6
Centers for Medicare & Medicaid Services. Marketplace Verification of Citizenship and Immigration Status
7
HealthCare.gov. Health Coverage Options for Incarcerated People
8
Office of Personnel Management. Privacy Impact Assessment for FEHB Data Hub
9
Centers for Medicare & Medicaid Services. How Is Affordability Determined for Offers of Employer-Sponsored Coverage and How Does That Relate to Eligibility for Advance Payments of the Premium Tax Credit
10
Centers for Medicare & Medicaid Services. Resolving Data Matching Issues
11
Centers for Medicare & Medicaid Services. Post-Enrollment Assistance – Resolving Data Matching Issues
12
HealthCare.gov. Health Plan Required Documents and Deadlines
13
HealthCare.gov. How to Appeal a Marketplace Decision
14
Office of the Law Revision Counsel. United States Code Title 5 – Section 552a
15
Centers for Medicare & Medicaid Services. The Marketplace and Cybersecurity