MCS-90 Endorsement

The MCS-90 is a federal endorsement required by FMCSA on interstate motor carriers' primary liability policies. It guarantees that if the carrier's normal liability coverage somehow fails to respond, the insurer will still pay claims up to the federal minimum to protect the public. It does not replace primary liability — it's a safety net mandated by federal law. Carriers are typically allowed to seek reimbursement from the insured under the endorsement's terms.