Occurrence vs Claims-Made
Two fundamentally different policy triggers that determine when coverage applies. The choice affects long-tail exposure for tower contractors whose structural work must perform safely for decades after installation.
Occurrence Form
Advantages
- +Covers claims regardless of when they are reported, as long as the injury or damage occurred during the policy period
- +No need to purchase tail coverage when switching carriers or retiring the policy
- +Provides peace of mind for completed tower installations that could produce claims years later
- +Preferred and often required by tower clients and general contractors in MSA language
Disadvantages
- -Higher premiums due to the insurer's open-ended exposure window
- -Carriers may restrict availability for newer tower companies without established loss history
- -Rate increases at renewal reflect industry-wide loss development, not just the individual insured's experience
Claims-Made Form
Advantages
- +Lower initial premiums, especially in the first few policy years as the retroactive date matures
- +More commonly available for professional liability and pollution coverage where occurrence forms are rare
- +Allows precise budgeting since claims must be reported within a known window
Disadvantages
- -Requires continuous renewal or tail purchase to maintain coverage for prior work
- -Tail coverage can cost 150% to 250% of the expiring annual premium
- -Creates a gap if the retroactive date is advanced during a carrier change
- -Most tower MSAs explicitly reject claims-made CGL policies
Bottom line for tower contractors
Occurrence is the standard for tower contractor CGL. Claims-made is acceptable only for professional liability or environmental policies where occurrence forms are unavailable. Never accept a claims-made CGL if the work involves structural installation or antenna mounting.