The Stop ACA Enrollment Fraud Act of 2026 amends the Affordable Care Act to combat fraud in health insurance marketplaces. The bill requires the federal government to establish a system within 60 days to detect and prevent duplicate enrollments by checking whether applicants' Social Security numbers match other enrollees in the same time period, ensuring people cannot fraudulently receive tax credits for multiple health plans. Additionally, starting January 1, 2027, the bill mandates that enrollments made through insurance agents or brokers in the individual and small group markets must include direct, verified consent from the actual applicant or employer—meaning brokers cannot simply attest that they have consent on behalf of their clients. These changes affect individuals and small employers purchasing health insurance through the ACA exchanges, as well as the agents and brokers who help enroll them. The legislation aims to reduce fraudulent claims on federal premium tax credits by closing loopholes that allow multiple concurrent enrollments and unauthorized enrollments by brokers.