Special Form vs Basic vs Broad Form (Property)
Every commercial property declaration lists a "Causes of Loss" form — one of three ISO standard forms that determines what's covered. The form name is unfortunately written in industry shorthand (e.g., "CP 10 30"), and most business owners never realize they have a choice or that the form drives 30-50% of the premium.
Plain-English: Special Form (CP 10 30) is open-peril — it covers all direct physical losses unless specifically excluded. Basic Form (CP 10 10) and Broad Form (CP 10 20) are named-peril — they cover only the specific causes of loss listed on the form. Anything not listed = not covered.
Side-by-side
| Dimension | Special Form (CP 10 30) | Basic / Broad Form (CP 10 10 / CP 10 20) |
|---|---|---|
| Coverage trigger philosophy | Open-peril. All direct physical loss is covered unless specifically excluded by the policy. Carrier has burden of proving exclusion. Better for unusual or unexpected losses. |
Named-peril. Only losses caused by listed perils are covered. Insured has burden of proving the loss was caused by a listed peril. Losses from unlisted causes (e.g., a falling tree if "trees" aren't listed) are not covered. |
| Perils covered | Everything not excluded. Standard exclusions include: ordinance & law, earth movement, government action, nuclear, war, water (flood/sewer back-up — unless endorsed), fungus, wear & tear, dishonest acts, defective design. |
Basic Form (per ISO CP 10 10): Fire, Lightning, Explosion, Windstorm or Hail, Smoke, Aircraft or Vehicles, Riot or Civil Commotion, Vandalism, Sprinkler Leakage, Sinkhole Collapse, Volcanic Action. |
| Typical premium difference | 15-50% higher premium than Basic or Broad form for the same insured value, depending on building type and territory. The cost of open-peril coverage breadth. |
Basic is cheapest. Broad runs ~10-15% more than Basic. Both well below Special Form. |
| Who should choose Special | Most commercial property buyers when budget allows. Specifically: businesses in non-coastal/low-cat-loss areas, businesses with valuable contents, businesses without a strong inventory of known-peril exposures. |
Older buildings facing exclusions on Special anyway. Property where the only realistic loss exposures map to the named perils (e.g., a metal-frame industrial shed in a low-loss area). |
| Theft coverage | Generally included for both building and BPP (subject to exclusions for after-hours building theft on certain forms). Standard. |
Basic Form does NOT include theft. Broad Form does NOT include theft. Theft requires either Special Form or a named theft endorsement. |
| Common mistake at quote | Buyers select Basic to save 20% on premium without realizing theft isn't covered, falling-tree damage isn't covered, vandalism beyond specific listed scenarios isn't covered. The savings evaporate at first claim. |
Most people don't know which form they have. Pull your declarations page, find the "Causes of Loss" section, and confirm. If it says CP 10 10 or CP 10 20, you're on named-peril. |
Bottom line
Default to Special Form (CP 10 30) for most commercial property unless budget is hard-constrained or your specific risk profile demonstrably maps to only the listed perils.
Consider Basic or Broad Form only when:
- Your building/BPP isn't theft-exposed (rare)
- You've identified specific loss scenarios that map cleanly to the named perils list and don't see broader exposures
- You're cost-constrained and can absorb the breadth gap
If your current policy is on Basic or Broad, request a Special Form quote at next renewal. The premium increase (15-50%) is often surprisingly modest compared to the gap exposure, especially if your industry has experienced any non-standard claims trend (theft, vandalism, weather, falling objects).
Related guides
Sources cited
- Causes of Loss Form — Special (ISO CP 10 30) — International Risk Management Institute (IRMI), 2024
- Causes of Loss Form — Basic + Broad (ISO CP 10 10 / CP 10 20) — International Risk Management Institute (IRMI), 2024
- Named perils vs open perils coverage triggers — International Risk Management Institute (IRMI), 2024