What causes FMCSA to revoke an MC number?
The most common causes of MC revocation are insurance lapse (BMC-91 cancels and is not replaced), failure to maintain a current BOC-3 process-agent designation, unsatisfactory new-entrant audit, an out-of-service order, unpaid civil penalties, and serious safety violations resulting in a §385 unfit fitness rating. A missed MCS-150 biennial update deactivates your USDOT number and bars you from operating, but it is not an MC-authority revocation. Overdue UCR (Unified Carrier Registration) does not by itself trigger FMCSA revocation - UCR is enforced by the states through roadside citations and fines. Voluntary revocation (carrier requests deactivation) is also possible and follows the same procedural path.
Insurance lapse is the leading cause of involuntary MC revocation. When the BMC-91 cancels and the carrier fails to file replacement coverage, FMCSA initiates the §387 enforcement process: the operating authority is suspended, then revoked if the carrier does not remedy within the §387 timeline. Most insurance-lapse revocations happen within 60 days of the original cancellation effective date if no replacement is filed.
BOC-3 lapse is less common but does happen, typically when a carrier's process-agent provider loses its FMCSA blanket-agent standing (invalidating the BOC-3 on file) and the carrier doesn't notice. The §366.4T obligation to maintain a current designation never goes away; if SAFER shows the BOC-3 status as expired or the named provider as unauthorized, FMCSA enforcement follows the §366 procedural path to revocation.
The MCS-150 biennial update is a separate record and a separate penalty. It is due every 24 months on the schedule keyed to your USDOT number (the last digit sets the month, the next-to-last digit sets the odd or even year). Miss it and FMCSA deactivates your USDOT number and you are prohibited from operating, with civil penalties available under 49 USC §521(b)(2)(B) - see 49 CFR §390.19(b)(4), §390.19(g)(2), and §390.201. What a missed biennial update does not do is revoke your MC authority. File a fresh MCS-150 to reactivate the USDOT number; longer lapses may trigger more comprehensive reinstatement requirements.
UCR non-payment under 49 USC §14504a is often listed alongside these, but it works differently. UCR fees are due annually based on fleet size and the program is administered and enforced by the participating states, not FMCSA: an unregistered carrier faces roadside citations and fines under state law. FMCSA does not revoke MC authority for an overdue UCR filing on its own - revocation is driven by the insurance, BOC-3, out-of-service, penalty, and safety-fitness paths above. Keep UCR current because state enforcement is expensive, not because it threatens the MC number directly.
Safety-driven revocation under §385 is the most severe path - an unsatisfactory fitness rating after a compliance review, repeated OOS violations on PSP, or serious crashes leading to FMCSA out-of-service orders. These are rare for most carriers but always loom for high-volume operators with thin safety margins.