Definition:Duty to defend
🛡️ Duty to defend is the obligation of a liability insurer to provide and fund a legal defense for its insured when a third-party claim or lawsuit alleges facts that could potentially fall within the scope of the policy's coverage. This duty is distinct from — and broader than — the duty to indemnify: an insurer may be required to defend a suit even if the claim ultimately turns out not to be covered, so long as the allegations, taken at face value, raise the possibility of a covered loss.
📜 Whether the duty is triggered is typically determined by comparing the allegations in the complaint (or equivalent pleading) against the insuring agreement, exclusions, and conditions of the policy. Most jurisdictions follow the "four corners" or "eight corners" rule — looking only at the complaint and the policy — though some allow the insurer to consider extrinsic evidence. Once triggered, the insurer usually selects and pays defense counsel, controls the litigation strategy (subject to ethical constraints), and bears all defense costs. In many policy forms, defense costs are paid in addition to the policy limits, though claims-made and certain professional liability policies may erode limits with defense spending.
⚠️ Failing to honor the duty to defend carries severe consequences. Courts in many jurisdictions hold that an insurer that wrongfully refuses to defend is estopped from later denying coverage — effectively converting a questionable claim into a fully covered one. This exposure makes duty-to-defend determinations among the highest-stakes decisions in claims handling. Carriers invest heavily in coverage-opinion workflows, and claims professionals must navigate tensions between controlling defense costs and preserving the insured's right to a competent defense. In commercial and specialty lines, disputes over this duty generate substantial coverage litigation and shape the dynamics of settlement negotiations.
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