Can I have both an MC and an MX number?

MC numbers are the standard FMCSA operating-authority number for most carriers. The §365 framework covers carriers that are US-domiciled, Canadian-domiciled (operating across the US-Canada border), and any other non-Mexican carrier seeking US operating authority. The OP-1 application is the entry point for an MC; the OP-1(P) for passenger authority and OP-1(FF) for freight forwarder authority are MC variants.

MX numbers are specific to Mexican-domiciled long-haul carriers operating into the US under §365.501. The OP-1MX application covers the cross-border long-haul authority. The MX number is functionally equivalent to an MC for FMCSA jurisdiction purposes - same §387 financial-responsibility requirements, same §366 process-agent requirements - but the issuing process and ongoing oversight is Mexico-specific.

A single legal entity can hold both an MC and an MX if it has operations in both jurisdictions. More commonly, carriers form separate corporate entities for cross-border operations: a US LLC with the US MC, and a Mexican S.A. de C.V. with the MX. The two entities operate independently for FMCSA purposes; equipment and drivers are typically shared via lease arrangements.

For most owner-operators and small fleets, the MC vs MX question is moot - the carrier domicile determines which number applies. US-domiciled carriers default to MC; Mexican-domiciled carriers default to MX. The rare carriers that hold both have substantial cross-border operations and sophisticated multi-entity legal structures to support them.