One of the most frequent questions we get from new motor carriers is whether the MCS-90 and the BMC-91X are different names for the same form. They aren’t. Both relate to your liability insurance, both are filed with FMCSA, and both are required for active operating authority — but they do distinct jobs.
MCS-90 — endorsement on your policy
The MCS-90 is an endorsement physically attached to your primary liability policy. It guarantees that, regardless of any policy exclusion, your insurer will pay claims up to the federally required minimum financial responsibility set by 49 CFR § 387.9: $750,000 for general freight, $1M to $5M for hazmat depending on cargo class.
You don’t typically file the MCS-90 itself with FMCSA. Your insurer attaches it to your policy and you keep a copy in the truck.
BMC-91 / BMC-91X — proof of filing
The BMC-91 (or BMC-91X for split-coverage policies) is the federal filing your insurer sends to FMCSA confirming that you carry the required liability coverage. It shows up in the public Licensing & Insurance database against your USDOT number. Without an active BMC-91/91X on file, FMCSA cannot grant or maintain operating authority.
The “X” version is used when you have two insurers — for example, primary $1M plus an excess layer of $4M. Each insurer files its own piece.
Why the distinction matters
If your policy lapses, your insurer notifies FMCSA automatically and the BMC-91X is cancelled. You have 30 days to file replacement coverage before FMCSA revokes your authority. The MCS-90 endorsement doesn’t have a separate cancellation — it lives or dies with the underlying policy.
When carriers switch insurers, both pieces have to update cleanly: the new insurer attaches its own MCS-90 to the new policy, and files its own BMC-91X with FMCSA. The old insurer’s BMC-91X cancels. If timing is wrong, you can spend a week without active filings on record.
We coordinate these transitions so they happen on the same day, not seven days apart. See Insurance & Federal Filings for the full process, or call +1 (310) 737-2842.