The federal government wants to resolve questions about enrollees' eligibility. Consumer advocates said many may be required to repay some or all of the subsidies.
Two of the eight million people who signed up for an exchange health plans reported personal information that differed from government data.
The government wants additional verification of enrollees' income, citizenship, immigration status, Social Security numbers and any employer-related health coverage. People who do not provide the information risk losing their subsidized coverage and may have to repay subsidies next April.