A-P02 · TOPIC · retrocession-and-capitalGRA dossier · service level R0
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Topic dossier · Reinsurance and Catastrophe

Retrocession and capital

Reinsurers buy protection too, through retrocession, and draw capital from investors through catastrophe bonds, collateralised reinsurance, sidecars and industry loss warranties. This capital backs the tail of catastrophe risk and its availability shifts with losses and returns elsewhere. This page sets out how retrocession and alternative capital work, how they are measured, and who decides.

The interactive map needs JavaScript; the layer list and sources are below.

Layers 2

Activity and exposure, for this page

Latest available

NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth

Loading the latest NASA imagery.

Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.

For retrocession and capital, in GRA's spatial-finance reading, the map opens on night lights and population density with built-up and settlement extent from NASA GIBS, framed on the Gulf of Mexico coast; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.

Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · GDACS · CIESIN/Columbia, NASA SEDAC HBASESources and licences

  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). CC BY 4.0
  • VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
  • © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). ODbL
  • Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
  • Globe: MapLibre GL JS 6.9.1, BSD-3-Clause, © MapLibre contributors.
  • Live: GDACS (EC JRC / UN OCHA) Events are indicative, not official warnings.
  • Context: CIESIN/Columbia, NASA SEDAC HBASE. Center for International Earth Science Information Network (CIESIN), Columbia University, and NASA Socioeconomic Data and Applications Center (SEDAC): Global Human Built-up And Settlement Extent (HBASE) 2010; Seto, Guneralp and Hutyra 2012, Global Grid of Probabilities of Urban Expansion to 2030; Global Urban Heat Island (UHI) Data Set, 2013.
  • Optional layers (35 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.

Layers and dates

  • Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
  • Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
  • Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
  • Land surface temperature, day, 8-day composite: VIIRS NOAA-20 Level 3, 8-day, NASA LANCE · 14 Sep 2026
  • True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
  • Active fires and thermal anomalies, last day: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026

01In brief

The short answer.

Retrocession is reinsurance bought by reinsurers; alongside it, catastrophe bonds, collateralised reinsurance and sidecars bring capital-market investors into the tail of catastrophe risk. Collateral, triggers and capital availability shape capacity. Reinsurer boards, investors, sovereign issuers and supervisors hold the decisions.

02Console

Catastrophe model results, in outline.

The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.

Catastrophe model results

Retrocession and capital · Cedent C-07 · Peril: tropical cyclone

  • AAL
    40local m
  • OEP 1-in-200
    285local m9Watch
  • TVaR 1-in-200
    396local mWatch
  • Rooftop geocoding
    86pct of TIVNormal
1-in-200 above retentionGRA · Reinsurance and Catastrophe

Exceedance probability

Programme layers

Retention070n/a
Layer 1766181-in-14
Layer 213416841-in-49
Layer 33971881.21-in-157

Model pipeline

  1. Event cataloguestochastic
  2. Hazardintensity
  3. ExposureTIV
  4. Vulnerabilitydamage curves
  5. Financialterms
  6. ELT · YLTlosses
  7. EP · TVaRmetrics
Catastrophe model results: the screen's structure, terms and states for Retrocession and capital.Placeholder names and illustrative values; a design, not a record or a live system.
03The question

Retrocession and capital: how the risk develops.

Layered risk-transfer market dependencies. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mechanism

Capital markets enter the tail

Insurance-linked securities let investors take catastrophe risk for a return uncorrelated with most assets. Fully collateralised structures remove counterparty risk.

Mechanism

Collateral can be trapped

After a large event, collateral is held until losses are known, which can take years. Trapped capital reduces capacity at the next renewal.

Mechanism

Retrocession spirals

When reinsurers protect each other, losses can circulate within the market. Spirals concentrate losses and obscure who ultimately bears them.

Mechanism

Triggers create basis risk

Indemnity, industry index, parametric and modelled loss triggers differ in transparency and basis risk. Investors and cedants trade one against the other.

04Key terms

Terms used on this page.

Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.

TermDefinition
Catastrophe bondA security whose principal is reduced if a defined catastrophe triggers a payout to the sponsor.
Collateralised reinsuranceReinsurance fully backed by collateral held in trust, often provided by capital-market investors.
Trapped collateralCollateral held after an event until losses are known, unavailable for new risk.
05Indicators

What is measured, and how well.

Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.

IndicatorUnitCadenceSource typeLabel
Alternative reinsurance capitalcurrencyquarterlyBroker and industry reportsREPORTED
Catastrophe bond issuancecurrency per yearannualTransaction directoriesREPORTED
Catastrophe bond outstanding by trigger typecurrency by triggerquarterlyTransaction directoriesREPORTED
Catastrophe bond spreadbasis points over risk-free rateper issuanceOffering documents and market dataOBSERVED
Expected loss of issued bondspercent per yearper issuanceOffering documentsMODELLED
Trapped collateral after eventscurrencyper eventIndustry reportsESTIMATED
06Canvas

From sources to decisions.

The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.

Pipeline canvas · Retrocession and capital as a run graphDesign, not a record
Retrocession and capital: parametric trigger design and paymentA peril and an index are chosen, the trigger and payment structure designed and tested for basis risk, priced and contracted; a calculation agent monitors the index, calculates the payment and funds flow to pre-agreed delivery. Design of the process, not a record of a run.

Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.

07Sources

Where the evidence comes from.

Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.

SourceWhat it givesLicence class
Artemis deal directoryCatastrophe bond and ILS transactionsProprietary, free to read under terms
Swiss Re Global Cat Bond IndexTotal return index of catastrophe bondsProprietary, published summaries
Bermuda Stock Exchange ILS listingsListed insurance-linked securitiesFree to read, BSX terms
World Bank catastrophe bond programme documentsSovereign catastrophe bonds issued through the World BankFree, World Bank terms
Aon and Gallagher Re capital reportsReinsurance and alternative capital estimatesProprietary, reports free to read
08Decisions

Who decides, and what the evidence serves.

Reinsurance and Catastrophe prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Who decidesThe questionEvidence this page serves
Reinsurer boardsHow much retrocession and alternative capital to rely onCapacity, price and counterparty evidence
ILS fund managers and institutional investorsWhether and how to allocate to catastrophe riskModel output, trigger terms and past loss experience
Sovereign issuers and finance ministriesWhether to issue catastrophe bondsCost comparisons and basis risk evidence
Supervisors of special purpose insurersWhether vehicles are fully funded and well governedCollateral and governance records

Outputs this topic produces

  • Guide to insurance-linked securities and trigger types
  • Brief on trapped collateral and capacity
  • Method note on reading catastrophe bond offering documents
  • Questions for boards on retrocession dependence
09Core questions

What experts ask about layered risk transfer.

  • How do losses move through retrocession and capital market layers?
  • How does capital from outside the traditional industry behave after large events?
  • How can the same risk be counted more than once in a chain of transfers?
  • How transparent are exposures at the top of the chain?
  • How do layered structures affect system resilience?
10Mechanisms and drivers

How layered risk transfer works.

Retrocession lets reinsurers manage their peak exposures. Capital market instruments transfer catastrophe risk to investors, who receive returns in exchange for bearing losses if specified events occur. These instruments are typically fully collateralised, which reduces credit risk.

Layers create dependencies. In past market cycles, retrocession capacity tightened after large loss years, and some losses proved larger or slower to settle than expected, trapping collateral. Chains of transfer can also make it hard to see where risk ultimately sits, a concern known as spiral risk when the same exposure circulates among participants.

Capital from outside the industry has added capacity and diversification. Its behaviour after losses depends on investor appetite and the returns available elsewhere.

11Methods and data

Methods and their limits.

  1. 01

    Market structure analysis

    Studying how capacity flows through layers. Data on private transactions are limited.

  2. 02

    Loss development studies

    Examining how losses develop over time after events. Each event differs.

  3. 03

    Network analysis

    Mapping chains of risk transfer. Counterparty information is confidential.

  4. 04

    Tail correlation analysis

    Examining how layers respond to extreme events, using extreme value theory.

This topic examines structure and dependencies. It does not discuss pricing, capacity or terms, and does not assess any instrument.

12Methods

How it is studied, and what the methods cannot say.

  1. Extreme value theory and tail riskPricing high excess layers · Hazard return levels · Tail dependence between perilsApplied here
  2. Actuarial mathematicsLayer pricing from model output · Blending experience and exposure rating · Capital allocationApplied here
  3. Uncertainty quantification and model validationPrimary and secondary uncertainty · Sensitivity ranking · Multi-model ensemblesApplied here
13Questions

Questions and answers.

What is a catastrophe bond?
A security that pays investors interest and returns principal unless a defined catastrophe triggers a payout to the sponsor, in which case investors lose part or all of the principal.
What is retrocession?
Reinsurance bought by reinsurers to protect their own portfolios, passing part of the assumed risk on again to other reinsurers or to capital-market investors.
What is basis risk?
The difference between the payout a contract gives and the loss the protected party actually suffers, highest for parametric and index triggers.
Does GRA arrange catastrophe bonds?
No. GRA does not arrange, advise on or solicit any transaction. This topic explains structures as research.
What is trapped collateral?
Collateral held back after an event while losses are still uncertain, which delays its return to investors.
Can the platform discuss market capacity?
No. Capacity and pricing are competitively sensitive and outside the platform's work.
Why does transparency matter?
Because chains of transfer can obscure where risk ultimately sits, which matters for system resilience.
Reinsurance and Catastrophe

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