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  3. CU-00-01

What it does

CU 00 01 is ISO's only commercial umbrella coverage form. It is occurrence based and pays the insured's "ultimate net loss" in excess of the "retained limit" for bodily injury and property damage (Coverage A) and personal and advertising injury (Coverage B). The retained limit is the available limit of the underlying insurance scheduled in the declarations, or the self-insured retention for occurrences or offenses the underlying policies do not cover. The insurer must defend when the underlying insurance does not cover a suit or its limits are exhausted, and takes over defense when underlying limits are used up.

ISO filed a revised 06 26 edition with the CU-2025-OFR25 multistate forms revision; the 04 13 and 12 07 editions remain on many in-force policies. ISO does not file a claims-made umbrella form in this program; underlying claims-made coverage is handled with CU 27 00.

Who needs it

Nearly every commercial account that carries general liability, auto and employers liability can use umbrella limits. Contracts, leases, lenders and franchisors commonly specify umbrella or excess limits, and contractors, trucking firms, property owners and manufacturers face verdicts that exceed primary limits.

Key provisions

  • Who is an insured: named insureds and their employees and volunteers within limits, permissive users of covered autos, and any additional insured under the underlying insurance, automatically. When a contract requires the additional insured coverage, the umbrella pays no more than the contract requires, less underlying amounts, and is never broader than the underlying coverage. ISO has no separate umbrella additional insured endorsement.
  • Other insurance: the umbrella is excess over and does not contribute with any other insurance, primary or excess. Contracts that demand primary and noncontributory umbrella coverage need CU 24 77 or CU 24 78.
  • Limits: an each occurrence limit, a personal and advertising injury limit and an aggregate that applies to Coverage A except auto bodily injury and property damage, and to Coverage B.
  • Exclusions include expected or intended injury, contractual liability (other than insured contracts), liquor, workers compensation, ERISA, auto coverages other than covered autos and first-party auto coverages, employers liability, employment practices, pollution, aircraft and watercraft, professional services and others. Several exclusions (liquor, employers liability, pollution, aircraft or watercraft) do not apply to the extent valid underlying insurance exists for the risk, and then coverage follows the underlying provisions.
  • Maintenance of underlying insurance: if the insured lets underlying coverage lapse, the umbrella still applies as if the underlying were in force, so the insured absorbs the gap.

Quoting and selling notes

  • Get the schedule of underlying insurance: CGL, auto and employers liability policies with carriers, limits and forms, and any liquor, aircraft, watercraft or professional coverage you want the umbrella to follow.
  • Confirm the carrier's minimum underlying limits before quoting, and line up the policy periods; CU 24 37 (Non-Concurrency Of Policy Periods – Retained Limit) addresses underlying policies on different terms.
  • Ask about contracts requiring additional insured, primary and noncontributory or waiver of subrogation status on the umbrella; add CU 24 77/CU 24 78 and CU 24 03/CU 24 80 as needed.
  • Review the exclusion endorsements attached to the quote (abuse or molestation, cyber incident, PFAS, assault or battery, generative AI, communicable disease) against the client's operations.
  • Self-insured retention applies only where the umbrella covers something the underlying does not.

Related forms

Declarations CU DS 01; CU 24 77, CU 24 78, CU 24 03, CU 24 80, CU 21 11, CU 25 06, CU 27 00, CU 24 84, CU 24 85. Excess follow-form alternative: CX 00 01.