Insurance agents and brokers may have liability to third parties, not just their clients, in certain situations and states, and this may increase losses under insurance agent/broker E&O (errors & omissions or professional liability) policies.
How can third party liability arise? A simple example would be the following: an agency fails to place an auto policy, and the owner of the vehicle injures a third party. The insurance is not in place and the owner does not have financial resources to compensate the victim. The victim sues the insurance agency claiming negligence. The legal question is whether the agency owes the victim a duty, in this case to place the insurance for the owner.
Some states allow a third party action and others do not. California is one state where agents and broker have avoided third party liability, but this may be changing according to an article (see here).