The MCS-150 (Motor Carrier Identification Report) is the form every carrier, broker, and freight forwarder registered with FMCSA must file to obtain or update their USDOT number — it captures basic company information like legal name, business address, fleet size, driver count, cargo classifications, and operation type (interstate/intrastate, hazmat, passenger, etc.). After initial registration, FMCSA requires carriers to re-file the MCS-150 every 24 months, on a schedule tied to the last two digits of their USDOT number, commonly called "biennial updating." A carrier that fails to update on schedule risks having its USDOT number deactivated, which can effectively halt its ability to operate legally, even if nothing else about the business has changed. Because the MCS-150 is self-reported, the fleet size, driver count, and cargo data downstream tools display come directly from what the company filed — they aren't independently audited, so a carrier's actual current fleet can differ from its most recent filing, especially if it's grown, shrunk, or is overdue for an update. The filing date itself is a useful signal of how current a carrier's on-file information likely is.
A carrier whose MCS-150 was last updated three years ago may be overdue for its biennial filing, which is worth noting since its listed fleet size may no longer be accurate.
The last filing date is shown in the Safety & Compliance section, and filing events appear in the Authority & Registration History timeline, on every carrier profile.