Non-Proportional CoversApplied

Loss Corridor

A deliberate hole in the middle of a cover

A band of loss that the cedent must bear alone even though it sits between two layers that are otherwise covered.

Open the interactive version → definition, quiz, structure diagram and progress tracking

Definition

A loss corridor (or loss ratio corridor) is a defined band — expressed either in loss ratio points or in dollars — within which the cedent retains 100% of the loss even though a quota share or excess-of-loss cover responds both below and above the corridor. It is a pricing tool: narrowing the reinsurer's exposure over a specific stretch reduces the premium, in exchange for the cedent carrying that one slice entirely alone.

It differs from an ordinary retention or attachment point, which is a single threshold below which the cedent pays and above which the reinsurer pays: a corridor reintroduces cedent-only exposure a second time, higher up, after cover has already started.
Loss corridors are common on quota share treaties as a loss-ratio-based band, for example the cedent bearing 100% of loss ratio from 80% to 100%, and occasionally on excess-of-loss layers as a dollar band placed deliberately inside an otherwise continuous tower.
The corridor exists to solve a specific incentive problem: without it, a cedent fully reinsured above a low attachment has little reason to control claims once inside the covered layer — a corridor keeps the cedent financially exposed exactly where its own claims handling still matters most.

Worked example

A quota share treaty reinsures 100% of loss ratio up to 80%, and 100% again above 100%, but the cedent retains the entire 80%-to-100% corridor itself. A year that closes at a 92% loss ratio leaves the cedent bearing the corridor portion alone, however the rest of the treaty responds.

The structure diagram for this term is in the interactive version.

Scenario · figures in USD

A deliberate gap inside an otherwise continuous tower

Westgate Mutual buys $10M xs $5M per occurrence, but the treaty carries a $3M loss corridor from $8M to $11M — inside that band, Westgate retains the loss alone even though cover resumes immediately above it. A $14M occurrence loss tests every part of the structure.

Gross occurrence loss	$14M
Retention (below $5M)	$5.0M retained
Layer below the corridor ($3M xs $5M)	$3.0M recovered
Loss corridor ($8M to $11M)	$3.0M retained — cover pauses here
Layer above the corridor ($4M xs $11M, partly used)	$3.0M recovered
Total recovered	$6.0M
Total retained by Westgate	$8.0M

So whatWestgate bought what looks like a $10M xs $5M tower and only recovered $6M of a $14M loss — because $3M of the span it thought it had reinsured was carved out as a corridor it always intended to keep. A corridor is cheaper cover precisely because it is less cover, in a specific place chosen at placement, not at claim time.

Check your understanding

What makes a loss corridor different from an ordinary attachment point or retention?

A corridor reintroduces cedent-only exposure a second time, inside a layer that is otherwise reinsured both below and above it. A single retention or attachment point only ever separates cedent-pays from reinsurer-pays once. A corridor reintroduces a cedent-only band a second time, higher up.

Why would a cedent agree to a loss corridor at all?

It lowers the premium in exchange for carrying a defined band of loss alone. A corridor is a pricing trade: narrower reinsurer exposure over a chosen band buys a cheaper rate on the rest of the cover.

Word problem

A cedent buys $12M xs $4M per occurrence with a $2M loss corridor running from $7M to $9M. Calculate the recovery on a $15M occurrence loss, splitting it into the retention, the layer below the corridor, the corridor itself, and the layer above the corridor.

Show a hint

Work bottom to top: retention, then the covered band below the corridor, then the corridor (nothing recovered), then whatever of the loss still remains for the covered band above it, up to the top of the programme at $16M.

Reveal the worked answer

Retention (below $4M) = $4M retained
Layer below the corridor covers $4M to $7M = $3M recovered
Corridor covers $7M to $9M = $2M retained, cover pauses here
Layer above the corridor covers $9M to $16M, the top of the $12M xs $4M programme; the $15M loss only reaches $6M into this band ($15M − $9M), recovered in full
Total recovered = $3M + $6M = $9M
Total retained by the cedent = $4M + $2M = $6M

The cedent recovers $9M of the $15M loss and retains $6M — $4M of ordinary retention plus the $2M corridor it agreed to carry alone. Check it against the whole: $9M recovered plus $6M retained is exactly the $15M loss, with the corridor doing precisely what it was priced to do.