The legal standard
MCL 500.3142(2) says PIP benefits are overdue if not paid within 30 days after the insurer receives “reasonable proof of the fact and of the amount of loss sustained.” Reasonable proof is not the same as conclusive proof. The insurer does not need to agree the claim is owed for the clock to start. If the insurer later loses, interest runs from the date the proof arrived, and the insurer’s good faith in withholding payment does not matter. See interest and attorney fees.
Two parts must be proved:
- The fact of the loss: the patient was hurt in a motor vehicle accident, you treated the patient, and the treatment relates to the injury.
- The amount: what you charged, by code and date of service, and, for treatment after July 1, 2021, enough to apply the fee schedule.
If you prove only part of a claim, that part becomes overdue 30 days after the insurer receives the proof. The rest becomes overdue once it is supported.
What courts have accepted
In Bronson Health Care Group v. Titan Insurance (2016), the insurer received itemized statements, a UB-04, medical records and a police report. The Court of Appeals held that this was reasonable proof and that an assigned-claims insurer could not take extra time beyond the 30 days to investigate whether the patient was eligible. In VHS of Michigan v. Allstate (unpublished, March 10, 2026), the court sent a hospital’s interest claim back because the trial court never decided when reasonable proof was received. The hospital pointed to its billing statements; the insurer pointed to a later email from counsel. That date is a fact question, and your records decide it.
A reasonable-proof checklist
| Item | Why it matters |
|---|---|
| CMS-1500 or UB-04 with CPT, HCPCS and ICD-10 codes, NPI and place of service | Proves the amount and lets the insurer apply the Medicare-based cap |
| Office notes, operative or procedure reports, therapy notes for each date of service | Proves the service happened and was reasonably necessary |
| Prescription or referral for the treatment | Insurers routinely deny therapy, DME and home care without one |
| A history that ties the condition to the crash, with the crash date | Proves the fact of an injury arising from a motor vehicle accident |
| Claim number, policy number and adjuster, or the MAIPF claim number | Directs the bill to the right file |
| Written notice of your claim under MCL 500.3112 | Protects your balance if the insurer pays someone else |
| Proof of delivery: portal receipt, fax confirmation, certified mail or clearinghouse acknowledgment | Fixes the date the 30 days start |
Home care agencies should add signed daily timesheets and the plan of care. For non-Medicare services, keep your January 1, 2019 charge master ready, since DIFS requires it for cost disputes. See home care agencies.
Bill within 90 days
MCL 500.3142(3), added in 2019, gives the insurer 60 extra days to pay if the bill is not provided within 90 days after the service. Billing late does not lose the claim, but it pushes the overdue date, and the start of 12% interest, back two months. It also brings each charge closer to the one-year-back line.
Record requests and explanation requests
- Reports and records. MCL 500.3158(2) requires a provider, on the insurer’s request, to furnish a written report of the patient’s history, condition, treatment and the dates and costs of treatment, and to let the insurer inspect and copy its records.
- Utilization review. See utilization review appeals. MCL 500.3157a treats every provider as agreeing to submit necessary records for utilization review. If the insurer asks for an explanation of unusual care within 30 days of the bill, you must respond within 30 days of the request (Mich Admin Code R 500.63). If the insurer wants records beyond what normally comes with a bill, it must pay a reasonable fee plus copying and mailing costs.
- Accuracy. Knowingly submitting false or misleading records to an insurer, the MCCA or DIFS is a fraudulent insurance act under MCL 500.3157a(2).
Answer every request on time and log the date. A request answered late gives the insurer an argument that proof was incomplete. A request answered promptly and completely gives you the argument that every day after is overdue.
Denials and tolling
A specific claim for payment tolls the one-year-back period until the insurer formally denies it, if you pursue the claim with reasonable diligence (MCL 500.3145(3)). Formal denials restart the clock from where it paused. Log the date of every denial and EOR with the date of service it covers.
If you cannot prove when the insurer got the bill, you cannot prove when interest started. Keep delivery receipts with each claim, not in a separate system.
Sources: MCL 500.3112, 500.3142, 500.3145, 500.3157, 500.3157a and 500.3158; Mich Admin Code R 500.63; Bronson Health Care Group, Inc v Titan Ins Co, 314 Mich App 577 (2016); Williams v AAA Michigan, 250 Mich App 249 (2002); VHS of Michigan, Inc v Allstate Ins Co (Mich App, unpublished, Mar 10, 2026).
Questions people ask us
What counts as reasonable proof for a provider bill?
The statute asks for reasonable proof of the fact and of the amount of the loss. In practice that means a properly coded claim form, the records supporting the service, and enough information to tie the treatment to the crash. In Bronson Health Care Group v Titan (2016), itemized statements, a UB-04, medical records and a police report were enough to start the 30-day clock.
Can the insurer keep asking for more records to delay payment?
It can ask, and MCL 500.3158(2) requires providers to furnish reports and records on request. But a request does not automatically stop the 30-day clock if what you already sent was reasonable proof. Keep proof of what you sent and when.
Who pays for copying records the insurer asks for?
Under the utilization review rules, if the insurer requests records beyond what normally accompanies a bill, it must pay a reasonable fee plus copying and mailing costs within 30 days (Mich Admin Code R 500.63).
Does sending a bill toll the one-year-back rule?
A specific claim for payment pauses the one-year period under MCL 500.3145(3) until the insurer formally denies it, as long as you pursue the claim with reasonable diligence. A complete submission makes that claim easier to prove.