The Deadline Asymmetry

Two clocks run on every denied claim, and they do not run at the same speed. One is the provider’s: the window to submit the claim, and then the window to appeal once it comes back denied. The other is the payer’s: the time it is allowed to take to answer. On the provider side the windows have been tightening for years — Medicare’s filing limit was cut to twelve months in 2010, and commercial payers publish filing windows as short as ninety days. On the payer side, the response clocks are set by federal regulation and have not moved. That gap is the asymmetry.

It matters because a missed deadline is not a lost argument — it is a claim that can never be argued at all. A late claim is denied on filing alone, and under most participation agreements the provider cannot then bill the patient for the balance. The window, not the merits, decides the money.

Aggregator sites publish tidy tables of “timely filing limits” that are often years stale and rarely sourced. The table below is built differently: every window is read from the payer’s own current provider page, and every cell links to it. Where a payer does not publish a single fixed number — because it defers to the participation agreement — the cell says so rather than inventing one. One payer we intended to include, Humana, was dropped: its provider pages were not publicly reachable for verification at capture, and citing a third-party guide would defeat the purpose.

The pattern in the verified cells is not that every payer is stingy — it is that the number a practice needs most is frequently not a number. UnitedHealthcare and Cigna both point providers to the participation agreement for the filing window; Aetna publishes appeal windows but treats the filing window as contract-governed. That is not obstruction so much as fragmentation: the operative deadline lives in a contract on a shelf, not on a public page. For a biller trying to work a stack of denials, a window they have to go find is functionally shorter than one they can look up.

The other side of the asymmetry is fixed in federal regulation. For an employer-sponsored (ERISA) or ACA plan, the internal appeal decision deadlines are set by the Department of Labor’s claims-procedure rule, 29 CFR 2560.503-1. For a group health plan, paragraph (i)(2) gives the plan, at the outer bound: not later than 72 hours for a claim involving urgent care; not later than 30 days for a pre-service claim where the plan provides a single appeal; and not later than 60 days for a post-service claim with a single appeal.⁷ Where a plan runs a two-level internal appeal, those post-service and pre-service figures are stated per level (30 and 15 days respectively).⁷

Read the two clocks together and the asymmetry is concrete. A post-service medical claim — the ordinary case — gives the plan up to sixty days to answer each appeal it decides, while the provider on a ninety-day filing contract may have fewer working days than that to assemble and submit the appeal in the first place. The side with the money to keep gets a comfortable, regulation-backed clock; the side trying to collect gets a contract clock that is often shorter and harder to find.

Separately, most states have prompt-pay laws that cap how long a payer may take to pay a clean claim — commonly on the order of thirty to forty-five days, with interest for lateness. Those laws vary widely by state and plan type, and self-funded ERISA plans sit outside them, so we mention the category without compiling it; a state-by-state table would be its own piece.

The mechanism is arithmetic, not drama. A filing or appeal window is stated in calendar days, but the clock does not start on a clean desk. The provider usually learns a claim was denied only when the remittance advice arrives, and a routine adjudication-and-posting cycle can consume the first stretch of the window before anyone can act. What is left is smaller than the headline number — and smaller still once weekends come out.

Multiply that by a queue. A small billing team is not working one denial against one clock; it is working dozens, each on its own window, many of them the “go find your contract” kind. When the working days left are few and the dollar value of a given claim is low, the rational move — the one the economics push toward — is to let the smaller denials lapse. The window converts delay into a write-off that never even becomes a line item. That is the quiet cost of the asymmetry: not the appeals that are lost, but the ones that are never filed because the clock ran first.

None of this is a reason to skip the fight — it is a reason to start it the day the remittance lands. The companion pieces below lay out the mechanics: how timely-filing rules work, how appeal deadlines are counted, and what to do with a CO-29 timely-filing denial — including the clearinghouse acknowledgment that is the strongest proof a claim went out on time.