What It Is

Cost Sharing Reduction (CSR) subsidies reduce out-of-pocket costs for eligible enrollees on Silver plans — but the federal government stopped making direct CSR payments to carriers in 2017. Since then, carriers have recovered those costs through their premium pricing: inflating Silver plan premiums to offset the unreimbursed subsidy obligation.

What hasn't been fully resolved is the reconciliation: a precise, member-level accounting of what each carrier actually incurred in CSR obligations versus what they received. That gap matters for rate development, litigation exposure, and in some states with their own CSR programs, financial settlement — and it's now becoming a formal compliance requirement.

CMS is requiring carriers to submit CSR reconciliation figures as part of their 2027 rate filings. Carriers that don't have a defensible, methodology-documented calculation in hand are going to be scrambling. The data work underlying it is non-trivial.

The Analysis

CSR reconciliation requires reconstructing, at the claim level, what each eligible enrollee actually paid versus what they would have paid under the standard Silver plan cost-sharing structure. The difference is the carrier's CSR incurred obligation for that member, that plan year.

That means working through:

• Enrollment files identifying CSR variant enrollment (73%, 87%, 94% AV Silver variants)
• Medical and pharmacy claims with adjudicated member liability
• Plan and benefits structure for each variant, mapped to service categories
• Applicable cost-sharing parameters (deductibles, copays, coinsurance, MOOP) for both the CSR variant and the standard Silver equivalent
• Aggregation to the HIOS ID level, plan year, and metal/variant tier

The output is a defensible, documented CSR incurred figure by member and b y HIOS ID — ready for rate filing submission and supporting documentation.

Our Offering

Evensun delivers a full CSR reconciliation engagement, from data intake through final deliverable. Our team brings CFO-level experience operating ACA plans alongside deep actuarial and data engineering capabilities — we've worked the other side of these numbers as plan operators, not just consultants.

What's included:

• Structured data intake with a defined data dictionary for enrollment, medical, and pharmacy claims
• Claim-level CSR liability calculation using plan benefits template service categories
• Aggregated reconciliation output by HIOS ID and plan year
• Methodology documentation suitable for rate filing support
• QA reconciliation against known anchors (enrollment counts, premium amounts, CMS payment data where available)

Pricing starts at $50,000 per HIOS ID.

Multi-HIOS ID and multi-year engagements are scoped individually. Contact us to discuss your specific situation.

Why Evensun

Most actuarial and consulting firms that do ACA work do it as one of many lines of business. We don't. The Individual Exchange is all we do — and our principals built careers operating ACA plans before starting Evensun. We understand how these numbers flow through a carrier's financials, not just how to calculate them.

Ready to get started? Contact us to discuss your HIOS IDs, plan years in scope, and timeline.