How do reinsurers manage catastrophe risk?

Catastrophe risk for a reinsurer is accumulation: many original policies, one event, one region, sometimes one hours clause. Management is not a slogan about diversification. It is a file of cited exposures, a wording that defines the event, a layer that attaches where it says it attaches, and a human who will not bind a share because a map looked busy.

You cannot manage what you cannot point at. If TIV, occupancy, geocode, and period are only in a covering email, the accumulation view is theatre. If the hours clause is missing, the event view is theatre.

How it works

Inward underwriting sets limits per cedent, class, territory, and peril in guidance. Software can extract those fields from a pack and flag that guidance has a view on coastal construction. Software should not auto-decline. Portfolio view then joins certificates and treaty exposures on the same peril and region. Conflicts stay visible. Gaps stay empty.

Protection is outward. CAT XOL on the reinsurer's own event losses. Sometimes quota share. Sometimes collateralized capacity. Sometimes a named facultative retro. Those contracts need the same event definition discipline as the inward book. Pricing still wants documents: exposure, large losses, model narratives as files. Quoted price remains a market decision.

After an event, the job is an event pack. Bordereaux with event date, paid, outstanding, policy references. Hours start. Attachment. Exhaustion. Reinstatement. IBNR is a reserve conversation with an as-at, not a plug to make the event look finished.

Worked example

ACME Construction Ltd, acme.example, sits in a coastal construction zone on a schedule that totals USD 47,100,000. The slip the market wrote said TIV USD 42,000,000 and USD 10,000,000 any one occurrence. A named windstorm later puts USD 8,400,000 on the warehouse. The cedent's event aggregate reaches USD 31,200,000 against a CAT XOL attaching at USD 25,000,000.

The reinsurer's accumulation view had to choose whether ACME's extra warehouse was in before the wind arrived. Leaving the TIV conflict visible is how a catastrophe desk asks the question. Hiding it inside a single modelled TIV is how the event total surprises everyone, including the retrocessionaire.

What goes wrong

Geocodes missing, so two warehouses stack on a city centroid. Bordereaux without event date. Hours clause paraphrased as 72 hours because that is what last year's storm used. Facultative originals omitted from the treaty accumulation because they lived in another mailbox. Outward retro placed on last year's attachment. Model output pasted without the vendor file, then treated as a signed term.

Related reading

Layer mechanics are what is CAT XOL reinsurance?. The inbound map is reinsurer operations. Treaty administration is treaty reinsurance.