Catastrophe retention is the amount of covered catastrophe loss an insurer retains before a catastrophe reinsurance layer begins paying. It is a core measure of how much event risk remains on the insurer's own balance sheet.
For an excess-of-loss treaty, the simplified structure is:
Insurer retains losses up to the attachment point; reinsurance responds above that amount, subject to the treaty limit and terms.
Simple example
Suppose a catastrophe treaty provides $400 million of coverage in excess of a $100 million retention.
- Losses from $0 to $100 million are retained by the insurer.
- Covered losses from $100 million to $500 million are within the reinsurance layer.
- Losses above $500 million may again fall to the insurer unless another layer responds.
The retention is therefore not the insurer's maximum possible catastrophe loss.
Event retention versus aggregate retention
A per-occurrence retention applies separately to a covered event. An aggregate retention applies to cumulative qualifying losses over a stated period, often a year.
These structures answer different questions. A per-occurrence program can protect against one large hurricane while leaving the insurer exposed to many smaller catastrophes that never individually exceed the event retention.
Retention versus deductible
Retention is sometimes described informally as a deductible, but investor analysis should use the treaty's own language. Reinsurance contracts can include co-participation, multiple layers, franchise features, exclusions, and aggregate terms that make the economics more complex than a simple policy deductible.
Retention versus net catastrophe loss
The final net loss from a catastrophe can exceed the headline retention because of:
- uncovered losses or excluded perils;
- co-participation within a reinsurance layer;
- limits or exhaustion;
- reinstatement premiums;
- loss adjustment expenses;
- timing or collectibility issues; and
- losses outside the covered occurrence definition.
A $50 million event retention does not mean every catastrophe is capped at $50 million of net economic cost.
Why investors care
A lower retention reduces the amount of first-dollar catastrophe loss the insurer absorbs, but it usually requires paying more ceded premium for reinsurance. A higher retention can reduce reinsurance cost while increasing earnings and capital volatility.
Neither direction is automatically better. The relevant question is whether the retained risk is appropriate for the insurer's capital, pricing, liquidity, and risk appetite.
Compare retention with PML and capital
Retention is most informative when considered alongside:
- Probable Maximum Loss;
- catastrophe reinsurance limits;
- aggregate protection;
- Reinsurance Exhaustion;
- shareholders' equity or statutory capital; and
- the frequency of catastrophe-exposed losses.
Real-world filing context
Mercury General disclosed catastrophe reinsurance that attached after a company retention and provided a stated amount of per-occurrence coverage. Palomar Holdings separately discloses catastrophe-event retention by peril.
Sources:
Bottom line
Catastrophe retention is the insurer's first layer of retained event risk before qualifying reinsurance responds. It should not be interpreted as a universal cap on net catastrophe losses, and it must be read together with limits, exclusions, participation, aggregate protection, reinstatement terms, and capital.
Continue Research
Continue from the concept into the Grizzly Bulls research surface that best matches the next question. These links are research continuations, not recommendations or required steps.
Compare retained catastrophe risk
Compare insurer capital and underwriting economics alongside event retention, co-participation, exclusions, and treaty limits.
Explore more topics in the Financial Research Encyclopedia.