Third-Party Liability Insurance

Third-Party Liability insurance, often shortened to TPL, is the broad family of insurance that responds when the policyholder is legally liable for harm caused to someone other than themselves or their direct contractual counterparty. The policy pays for the defense costs and the damages owed if the claim succeeds. The third party can be a customer, a member of the public, another business, a regulator, or anyone outside the policyholder's own organization who suffers loss.

It is the structural counterpart to first-party coverage, which responds to the policyholder's own losses (property damage to their own building, business interruption to their own operations, breach-response costs they incur themselves). Both kinds of coverage often sit inside the same policy: a Cyber form, for example, typically has a first-party section (breach response, business interruption) and a third-party section (regulatory and customer claims).

Most lines of commercial liability insurance are third-party in character. Commercial General Liability, Professional Liability, Tech E&O, Directors and Officers, and the third-party section of a Cyber wording are all built to answer claims brought by an outside party against the insured.

Generative AI Liability insurance is written as a third-party liability cover. The harm at issue is the harm done by the AI's outputs to someone else, and the policy responds to the claim that other party brings. The form does not cover the insured's own first-party losses from running a Gen AI system that breaks (that would sit under a different class of coverage entirely).

Testudo writes a standalone TPL form for U.S. enterprises deploying generative AI, structured as five named insuring agreements and backed by Lloyd's of London.