Glossary

Attachment point

The loss amount at which an excess, umbrella or reinsurance layer starts paying, normally the top of the underlying limits or retention beneath it.

Also called: attachment, point of attachment, excess attachment point

The attachment point is where a layer of coverage begins to pay. If an excess liability policy sits over a $1 million primary policy, it attaches at $1 million: the excess insurer owes nothing until covered loss reaches that figure, then pays up to its own limit. A $5 million layer attaching at $1 million is exhausted at $6 million. In a program with a self-insured retention, the retention can be the attachment point for the first layer. In reinsurance the same idea is called the retention.

How the underlying layer counts as used up matters as much as the number. The excess policy lists its "scheduled underlying insurance," and the attachment point is built on that schedule. Some forms require the underlying insurers to actually pay their limits; others let the insured fill a gap, and the wording differs on whether the insured's own payments count. If the primary limit turns out to be lower than the schedule says, say $500,000 instead of $1 million, the insured may owe the difference before the excess responds.

Aggregate erosion is the other trap. If claims from other occurrences have used part of the primary aggregate, the excess may or may not drop down, and the attachment point does not move. The guide on umbrella vs excess liability covers exhaustion wording and what to ask your broker to check at renewal.

Last reviewed October 10, 2026

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Related terms

Excess liability Liability coverage that pays only after the limits of underlying policies are used up, adding limit above them without necessarily broadening the terms. Umbrella policy A liability policy that adds limits above underlying general liability, auto and employers' liability policies and may cover some claims they do not. Retention The share of a loss a business pays itself, through a deductible, self-insured retention or captive, before insurance responds. Self-insured retention (SIR) The amount of a loss the insured must pay itself, often including defense costs, before the insurer's liability policy begins to pay. Following form An excess or umbrella policy that adopts the terms, conditions and exclusions of the policy beneath it, except where its own wording says otherwise.

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