The Obama administration estimates that 2.5 million more people could qualify for insurance subsidies if they bought plans on the Obamacare marketplaces instead of off them.

The federal subsidies to make coverage more affordable are available only for plans purchased through the marketplaces. Many people buy plans outside the marketplaces if they’re not eligible for subsidies anyway, but data released Tuesday by the Department of Health and Human Services shows some of those shoppers could be eligible for subsidies but just don’t know it.