An analysis from HHS said millions of additional customers could qualify for subsidies if they purchased plans off the Affordable Care Act (ACA) marketplace.

The agency estimated out of 6.9 million people who purchased coverage off the off-exchange individual market, 2.5 million may qualify for tax credits if they shopped on the ACA marketplace.

“More than nine million Americans already receive financial assistance through the Health Insurance Marketplace to help keep coverage affordable, but today’s data show millions more Americans could benefit,” HHS Sylvia Burwell said in a statement. “We encourage everyone to check out their options on HealthCare.gov or their state Marketplace and see if they qualify for financial assistance. Marketplace consumers who qualify for financial assistance usually have the option to buy coverage with a premium of less than $75 per month.”

Six states have more than 100,000 individuals who may be leaving subsidies on the table: California, Texas, Florida, North Carolina, Illinois and Pennsylvania.

Some of the off-exchange customers did have reasons not to shop for coverage.

“About 1.9 million either have incomes that would qualify them for Medicaid or place them in the Medicaid coverage gap or are ineligible to purchase Marketplace coverage due to immigration status, while the remainder could enroll in Marketplace qualified health plans,” HHS said.

If on and off-exchange customers were counted along with the uninsured who are eligible to use the marketplace, HHS said almost 80 percent of all marketplace-eligible Americans could receive income-based subsidies for buying coverage.

The agency has been trying to shine a spotlight on the availability of subsidies in reaction to increases in premiums in 2017 plans and the departures of major insurers like UnitedHealthcare, Aetna and Humana from many states.

Promoting subsidies isn’t likely to change the minds of ACA critics. When CMS Acting Administrator Andy Slavitt used their availability to defend the stability of exchanges in a congressional hearing, Rep. Tim Murphy, R-Pennsylvania, called that argument “absolutely phony.”