Starting with plan year 2028, ACA Marketplace applicants would have to pass eligibility verification before receiving any advance premium tax credits or cost-sharing reductions, replacing a system under which federal subsidies flow during unresolved data mismatches. That is the central operational change in a proposed rule the Centers for Medicare and Medicaid Services (CMS) published in the Federal Register on October 27, with a comment deadline of November 27.
The rule, CMS-9873-P, implements section 71303 of the Working Families Tax Cut (WFTC) legislation enacted July 4, 2025. Under the current system, an applicant whose information does not match federal data sources receives a data matching issue (DMI) and has 90 to 95 days to resolve it, during which advance premium tax credit (APTC) and cost-sharing reductions are paid.
The proposed rule ends that. Exchanges would be prohibited from authorizing subsidy payments for applicants with unresolved DMIs related to income and family size, citizenship or eligible noncitizen status, residency, or enrollment in other qualifying coverage, until those DMIs are adjudicated and eligibility is confirmed.
Applicants could still enroll in a full-price plan while verification is pending, with APTC applied retroactively once eligibility is confirmed, per the Federal Register text. Alternatively, they could select a contingent plan that is held and released to the issuer only after verification is complete. In that case, coverage and subsidies begin prospectively from the point of confirmation, with no retroactive payment. CMS acknowledges in the rule’s impact analysis that it ‘is unlikely that many consumers would be able to afford to enroll in a full-price QHP while they complete the verification process.’”
The second major change affects returning enrollees. Under current rules, existing Marketplace enrollees are automatically reenrolled with financial assistance. Under the proposed rule, an enrollee who does not return to the Exchange each year to confirm eligibility and have it re-verified would be reenrolled without APTC or cost-sharing reductions. A pre-open enrollment verification window, opening August 1 each year, would give consumers the option to submit eligibility information early. CMS proposes requiring all Exchanges to make that window available starting August 1, 2027, ahead of 2028 coverage.
The agency projects five million enrollees annually, nearly 30 percent of its 16.9 million 2028 baseline, will generate a DMI under the new process and receive APTC for an average of 1.5 fewer months while their information is resolved. An additional 332,500 enrollees are projected to exit the market each year, deterred by the verification process. At an average APTC of $655 per month, CMS estimates total subsidy payments would fall by $7.6 billion annually.
CMS projects a 0.4 percent average premium increase as a result of the enrollment shift, based on its assumption that exiting enrollees have claims running at 80 percent of the pool average. Actuaries pricing 2027 ACA plans applied a larger selection effect. KFF’s July 2026 review of rate filings found a 4-point morbidity load tied to subsidy-loss dynamics, a materially different assumption than CMS’ 0.4 percent. How the 2028 risk pool ultimately prices will depend on whether verification-related exits track closer to CMS’s administrative-barrier model or the market’s subsidy-driven selection model.
The rule arrives as 2027 open enrollment opens November 1, in a market that contracted sharply following enhanced subsidy expiration. Marketplace enrollment fell 12 percent to 19.2 million by February 2026 after enhanced premium tax credits expired at the end of 2025, and at least six carriers had announced exits ahead of 2027 open enrollment, with additional withdrawals reported in the months that followed.
Agents and brokers assisted 76 percent of active, consumer-initiated HealthCare.gov plan selections during the 2026 open enrollment period, according to CMS, meaning the operational changes the rule proposes will run largely through broker workflows.
A returning enrollee who does not proactively re-verify under the proposed rule would keep their plan but lose their financial assistance, receiving no APTC until they complete verification. Brokers whose clients currently coast through auto-reenrollment will need to replace that passive process with annual outreach timed to the August 1 verification window.
The rule is proposed, not final. Comments are due November 27. Implementation is set for 2028 coverage, with the first pre-open enrollment verification window on August 1, 2027.
