Truck insurance filings explained: BMC-91X, MCS-90 and more

Updated October 2026

Insurance for a trucking authority comes with paperwork that proves your coverage to regulators. Your insurer handles most of it, but you should know what each form is.

BMC-91 and BMC-91X

Proof of your liability coverage, filed by your insurer with the FMCSA. Your operating authority won't become active until it's on file. If your policy is canceled, your insurer notifies the FMCSA, which can lead to your authority being revoked.

BMC-34

Proof of cargo coverage, required for household goods movers.

MCS-90 endorsement

An endorsement on your liability policy that guarantees payment to the public for crashes, as required for many interstate carriers. It protects the public, not you; if your insurer pays a claim under it that your policy wouldn't otherwise cover, you can be required to pay the insurer back.

BOC-3

Not an insurance form, but often confused with one. It names a process agent in each state who can accept legal papers for you. Like the BMC-91, it must be on file before your authority is active.

Certificate of insurance (COI)

A one-page summary of your coverages and limits. Brokers and shippers ask for it before they give you loads, and many ask to be listed as a certificate holder. Your agent can send it the same day.

Try it: New authority insurance checklist

Educational information only, not insurance advice. Talk with a licensed agent about your coverage.