What it does
CX 00 01 is ISO's commercial excess liability form. It pays the insured's "ultimate net loss" in excess of the "retained limit", which is the available limit of the controlling underlying insurance scheduled in the declarations. It follows the provisions, exclusions and limitations of the applicable controlling underlying policy unless the excess form directs otherwise, and its coverage is never broader than that policy. Unlike the CU 00 01 umbrella, it has no self-insured retention and does not drop down to cover claims the underlying does not cover.
The insurer must defend once the applicable controlling underlying limits are exhausted. Any additional insured under the controlling underlying insurance is automatically an additional insured, limited to the amount the contract requires less the underlying amounts. ISO's SERFF schedules show the 04 13 edition as current; no newer CX 00 01 edition was found in ISO's 2025 filings.
Who needs it
Accounts that want higher liability limits at lower cost than an umbrella, buyers of excess layers above an umbrella, and insureds whose underlying policies already give the coverage breadth they need. Contracts that require "umbrella or excess" limits are usually satisfied by either form.
Key provisions
- Its own exclusions apply in addition to the underlying exclusions: medical payments, first-party auto coverages (physical damage, no-fault, PIP, uninsured/underinsured motorists), pollution unless valid underlying pollution coverage exists, and workers compensation.
- Limits: each occurrence and aggregate. The aggregate applies only to injury or damage that is subject to an aggregate under the controlling underlying insurance; if underlying limits are eroded by defense costs, so are the excess limits.
- A sublimit in the underlying (for example on abuse or liquor) is not followed unless it is shown in the declarations' schedule.
- Other insurance: excess over and non-contributing with all other insurance, unless an endorsement such as CX 24 32 or CX 24 33 changes it.
- If the controlling underlying insurer becomes insolvent, the excess insurer does not drop down to replace it.
Quoting and selling notes
- Get each underlying policy (CGL, auto, employers liability, umbrella) with forms, limits and dates; the excess follows these, so gaps in them become gaps in the excess.
- Check whether underlying limits include defense costs.
- Compare with CU 00 01 when the client needs coverage for claims excluded by the primary policies.
Related forms
CX DS 01, CX 24 32, CX 24 33, CX 21 10, CX 25 01; umbrella alternative CU 00 01.
