Umbrella policies were originally designed to offer additional limits and cover some of the gaps in the underlying coverage. They were not simply increased limits silos. They also provided a canopy or an umbrella that offered the insured a measure of protection from certain limitations in the underlying. If the umbrella covered something that the underlying did not cover, the insured paid a self-insured retention, usually in the range of $10,000 to $50,000, and then had coverage up to the umbrella's limit.
However, as primary commercial general liability coverage forms and policies became broader, the umbrella's additional coverage was reduced. It did not change but its coverage became narrower because the primary commercial general liability coverage became broader.
From the insured's perspective, there are no surprises or excitement in excess coverage forms and policies. All coverage disputes arise from the underlying coverage. Once the primary coverage is determined, the excess follows form by providing additional limits up to its ultimate limit. Excess coverage allows easy comparisons based purely on price and capacity.