What is the primary purpose of a personal umbrella policy?

A personal umbrella policy provides excess liability coverage above the primary policies' limits. It activates when an underlying policy limit is exhausted by a covered claim. It also broadens coverage in some areas not covered by underlying policies. Example: if auto liability pays $300,000 (its limit) on a $1,200,000 judgment, the umbrella pays the additional $900,000 (up to the umbrella limit). Umbrella policies require maintaining specified minimum underlying limits to activate.