If you hold interstate motor carrier authority, FMCSA wants proof you carry liability insurance. That proof comes through three documents that get confused all the time: the BMC-91, the BMC-91X, and the MCS-90. They sound similar, they sometimes show up in the same email from your broker, and most carriers I talk to think they are the same thing. They are not. This is a plain-English walkthrough of what each one does, when FMCSA requires it, who files it, and what happens when one of them is wrong.
Short version up front: the BMC-91 and BMC-91X are filings sent to FMCSA proving your liability policy exists. The MCS-90 is an endorsement attached to your auto liability policy that guarantees the public will be paid if you cause a crash. Filings prove coverage. The endorsement guarantees payment. Different jobs.
The legal source: 49 CFR Part 387
All three documents come from 49 CFR § 387.7, the federal regulation that sets minimum financial responsibility for motor carriers. The rule says any for-hire motor carrier operating in interstate commerce must maintain a minimum level of public liability insurance and must give FMCSA evidence of that coverage.
The minimum limits under § 387.9 have not changed in decades. For general freight in interstate commerce, the floor is $750,000 combined single limit. For oil, hazardous waste, and most placardable hazmat, the floor jumps to $1,000,000 or $5,000,000 depending on the commodity. In practice, almost no shipper or broker will tender freight to a carrier with less than $1,000,000, so the regulatory minimum is mostly a floor below the market.
The FMCSA's official summary of what filings are required for which authority type is here: FMCSA insurance filing requirements. Bookmark that page.
What is a BMC-91?
The BMC-91 is the standard certificate of insurance filed with FMCSA by your insurance company. It is filed electronically. You will never see a paper copy unless you ask for one. When the BMC-91 is on file, FMCSA's public Licensing and Insurance system (L&I) shows your liability coverage as "Active" with the insurer's name, policy number, effective date, and limit.
Key facts about the BMC-91:
- One insurer covers the entire required liability limit.
- The insurer transmits the filing directly to FMCSA. Your broker requests it.
- It typically posts in FMCSA's system within 24 to 72 hours of binding.
- If the policy cancels, the insurer files a BMC-35 cancellation notice and you have 30 days before authority is revoked.
According to FMCSA's L&I database, roughly 577,000 active interstate for-hire motor carriers had BMC-91 or BMC-91X filings on record as of 2024. That number moves a bit week to week as new authority is granted and old authority is revoked, but it gives you a sense of scale: the BMC-91 is the default filing for almost every interstate trucking operation in the country.
What is a BMC-91X?
The BMC-91X is the same idea as the BMC-91 with one difference: it is filed when two or more insurers split the required liability limit. The "X" stands for "excess" — meaning the filing covers a layered program.
Here is when this comes up in real life. Say a fleet needs to show $5,000,000 in liability because a shipper requires it. Most primary trucking insurers cap their net retention at $1,000,000. So the program is built as:
- $1,000,000 primary auto liability from Insurer A (files a BMC-91X for its $1M layer)
- $4,000,000 excess liability from Insurer B (files a BMC-91X for its $4M layer)
Each insurer files its own BMC-91X showing the slice it covers. FMCSA adds the layers together and recognizes the total as compliant. If one of the layers cancels, the carrier is out of compliance even if the other layer is still in force — the math has to add up to the required minimum.
About 15 to 20 percent of motor carriers I quote run a layered program, mostly because shipper contracts demand $2M, $3M, or $5M of combined liability that no single primary insurer wants to write on its own paper. If you operate auto haulers, oversize loads, tanker, or hazmat, you are almost certainly running a BMC-91X structure.
BMC-91 vs BMC-91X: a side-by-side
| Feature | BMC-91 | BMC-91X |
|---|---|---|
| Number of insurers | One | Two or more |
| Coverage structure | Single policy covers full FMCSA limit | Layered or split policies adding up to the limit |
| Who files | The single insurer | Each insurer files its own BMC-91X for its layer |
| Common use case | Owner-operator or small fleet at $750K–$1M | Fleet needing $2M, $5M, or hazmat $5M limits |
| Cancellation risk | One cancellation revokes coverage | Any layer canceling breaks the stack |
| FMCSA treats it as | Compliant proof of liability | Compliant proof of liability |
From FMCSA's point of view, both filings do the same regulatory job. The BMC-91X just acknowledges that real-world insurance markets often need to share a risk.
What is the MCS-90 endorsement?
The MCS-90 is not a filing. It is an endorsement physically attached to your commercial auto liability policy. It says: if you cause a crash involving bodily injury, property damage, or death, and your insurance company tries to deny the claim because of something in the policy fine print, the insurer will still pay the injured public up to the FMCSA minimum limit. The insurer then has the right to recover that money from you, the motor carrier.
Read that again. The MCS-90 protects the public, not you. If the insurer pays out under the MCS-90 because you were doing something the policy excluded — hauling a commodity you did not disclose, operating outside your authority, using a vehicle that was not on the policy — the insurer can come after you personally for reimbursement.
I wrote a longer piece on this here: MCS-90 endorsement explained. The short version is that the MCS-90 is FMCSA's safety net to make sure crash victims get paid even if the carrier and insurer are arguing about coverage.
According to the FMCSA insurance filing requirements page, the MCS-90 is required for every for-hire motor carrier of property operating in interstate commerce. It is generally not required for private carriers (companies hauling only their own goods) unless they are hauling certain hazardous materials.
How the three documents work together
Here is the order of operations when you bind a new commercial auto liability policy for an interstate for-hire carrier:
- You bind the policy with the insurer through your broker. The policy includes the MCS-90 endorsement automatically if you have for-hire interstate authority.
- The insurer issues the MCS-90 as part of the policy package. You should see it listed on your declarations page or in a separate endorsement form (Form MCS-90).
- The insurer files the BMC-91 or BMC-91X with FMCSA electronically. If it is a single-insurer program, that is a BMC-91. If it is a layered program, each layer files a BMC-91X.
- FMCSA updates your L&I record showing active liability coverage. Shippers and brokers running your authority will see "Active" status.
- If the policy cancels, the insurer files a BMC-35 cancellation notice. FMCSA gives you a 30-day grace window to file replacement coverage or your operating authority is revoked.
One thing that catches carriers off guard: the MCS-90 stays attached to your policy whether or not the BMC-91 is on file. The endorsement is part of the contract. The filing is a separate administrative step. You can technically have an MCS-90 on a policy that FMCSA does not yet know exists. That is why new carriers sometimes get a "no insurance on file" letter from FMCSA even though they bought a policy — the filing has not posted yet.
Who needs which filing
This is where carriers get the most confused. The short version:
| Carrier type | BMC-91 / 91X required? | MCS-90 required? |
|---|---|---|
| Interstate for-hire property carrier | Yes | Yes |
| Interstate for-hire passenger carrier | Yes (BMC-90 instead in some cases) | MCS-90B (passenger version) |
| Interstate private carrier (own goods only) | No | Only if hauling certain hazmat |
| Intrastate-only carrier | No (state filings instead) | No federally; state may require equivalent |
| Freight broker / forwarder | No (BMC-84 or BMC-85 bond instead) | No |
| Hazmat interstate carrier | Yes, at higher limits | Yes |
If you run an Indiana-based interstate operation, both the BMC-91 (or BMC-91X) and the MCS-90 apply to you. We cover the local market in detail on our Indiana commercial truck insurance page. Texas-based carriers see the same federal requirements; state-specific notes are on our Texas commercial truck insurance page.
Underwriting consequences of getting the filing wrong
This is the part nobody talks about until it bites them.
Late filing. If your insurer is slow to file the BMC-91, FMCSA will not show active coverage. Brokers running your MC number will see "no insurance on file" and refuse to tender loads. I have seen carriers lose a week of revenue waiting for a filing to post. Always confirm with your broker that the filing was transmitted on bind day, not "soon."
Wrong limit on the filing. If the BMC-91 shows $750,000 but your shipper contract requires $1,000,000, the shipper's compliance system flags you as non-compliant even though your policy might actually be at $1M. The filing has to match the actual policy limit.
Lapse between policies. If you switch insurers and the new BMC-91 does not post before the old one cancels, FMCSA shows a coverage gap. Even a one-day gap can trigger authority revocation proceedings. Schedule the switch so the new filing posts before the old one drops.
Layered program mismatch. On a BMC-91X stack, if the primary cancels but excess stays in force, FMCSA does not give you partial credit. The full required limit must be in force. This is why fleet renewals on $5M programs need to be coordinated across all layers.
MCS-90 reimbursement. If a crash happens and the insurer pays under the MCS-90 because the policy would have otherwise denied (commodity not disclosed, driver not on policy, etc.), the insurer can sue you for that money. The endorsement protects the public, not the carrier. This is a common surprise for owner-operators who switched policies and forgot to add a new trailer or commodity.
How to check your filing status
FMCSA's L&I system is public. Anyone can check any carrier's filing status. Here is how:
- Go to FMCSA Licensing and Insurance public search.
- Enter your USDOT number or MC number.
- Click "HTML" next to "Active/Pending Insurance."
- You will see the type of filing (BMC-91 or BMC-91X), the insurer name, the policy effective date, and the limit on file.
Check this every renewal. Check it after any insurer change. Check it any time a shipper or broker tells you your authority is showing as inactive. It takes 60 seconds and prevents most filing headaches.
What about cargo and bond filings?
Two more filings come up adjacent to the BMC-91 / 91X / MCS-90 set, and carriers often lump them in:
- BMC-32 / BMC-34 — cargo insurance filing. Required for household goods carriers. Not required for general freight, though many shippers contractually demand cargo coverage anyway.
- BMC-84 / BMC-85 — broker surety bond or trust fund. Required for freight brokers and forwarders, currently set at $75,000 under the MAP-21 statute. Not a motor carrier filing.
If you hold both motor carrier and broker authority on the same entity, you need both sets of filings. Most fleets keep the two authorities under separate LLCs to avoid commingling. If you run a layered fleet with broker authority, the fleet insurance conversation has to account for both.
Cost impact of filings
Filings themselves are administrative — most insurers do not charge separately for them, though some add a $25 to $100 fee per filing. The bigger cost is the underlying coverage that the filing represents.
According to FMCSA data and ATRI's 2024 Operational Costs of Trucking report, average commercial auto liability premiums for general freight carriers ran roughly $0.087 per mile in 2023, the highest on record. A typical over-the-road truck running 120,000 miles annually carries about $10,400 in liability premium per power unit at that rate, before considering physical damage, cargo, or excess layers needed for higher BMC-91X stacks. Owner-operators in their first year of authority tend to pay 30 to 60 percent above seasoned-fleet rates. We break down full premium ranges on our 2026 commercial truck insurance cost page.
FAQ
Can I file my own BMC-91?
No. Only a licensed insurance company can file the BMC-91 or BMC-91X with FMCSA. You request it through your broker, the insurer transmits it.
How long does it take a BMC-91 to post?
Most filings post within 24 to 72 hours of binding. If your filing has not appeared in L&I after 72 hours, ask your broker to confirm the insurer transmitted it.
Do I need a new MCS-90 every year?
The MCS-90 endorsement is attached to each new policy term. When you renew, the renewal policy includes a fresh MCS-90 with the new effective dates. You do not file it separately — it lives inside the policy.
What is the difference between BMC-91 and BMC-90?
BMC-90 is an older form historically used for the same purpose. FMCSA generally accepts the BMC-91 today as the standard. You will rarely see a BMC-90 referenced on new business.
If my authority is new, when do I need the filings?
FMCSA gives new carriers a window after authority is granted to submit insurance filings, typically before authority becomes active. You cannot operate in interstate commerce until the filings post. Plan to bind coverage at least a week before your intended start date.
Bottom line
The BMC-91 and BMC-91X tell FMCSA that you have liability insurance. The MCS-90 endorsement tells the public they will get paid if you cause a crash, even if the policy would otherwise deny. You need all three working correctly if you hold for-hire interstate motor carrier authority. Check your L&I record at every renewal, confirm the limit on file matches your policy, and coordinate any insurer change so the new filing posts before the old one drops. If you want a second set of eyes on your current filings or are shopping a renewal, you can request a quote and we will walk through your L&I record with you.
Written by Nazar Mamaev, Full Coverage LLC, Indianapolis, IN — published November 2025. Full Coverage LLC is an independent insurance brokerage and is not affiliated with FMCSA, USDOT, or any insurance carrier referenced in this article.