Insurance Curator Insurers revise catastrophe models and asset allocations as expanded severe‑event season squeezes combined ratios
By [Staff Reporter]
Who: Major insurers, reinsurers and catastrophe‑model vendors in the United States and Europe. What: They are recalibrating catastrophe models, tightening underwriting, raising reinsurance and rethinking investment portfolios. When: Changes accelerated after a string of costly 2024–2025 natural disasters and through the 2025 renewals and first half results. Where: Markets across North America and Europe, with outsized impacts in California and parts of the eastern United States. Why: Climate‑driven lengthening of wildfire and convective‑storm seasons, plus rising construction and replacement costs, have increased insured losses and pressured combined ratios, prompting modelling and investment changes. (businesswire.com)
The industry’s response has been multidimensional: catastrophe‑model vendors delivered new and upgraded wildfire and severe‑convective‑storm (SCS) modules; reinsurers and primary carriers tightened underwriting and sought higher rates at renewals; and investment officers rotated portfolios toward private credit, insurance‑linked securities and other alternatives to lift returns and create extra capacity for a higher‑loss environment. Executives and analysts say the moves reflect a recognition that an expanded, more destructive “severe‑event season” is not a short‑term anomaly but a structural shift driven by climate trends, urban growth and inflation in rebuild costs. (developer.rms.com)
How big the shock was — and who paid for it
The year‑end 2024 to mid‑2025 loss sequence that prompted the changes included a cluster of California wildfires in January 2025, severe convective storms across the U.S., and a run of impactful hurricanes in Atlantic basins. Early industry estimates of the insured loss from the Los Angeles‑area Palisades and Eaton wildfires ranged widely — CoreLogic put combined property and business interruption losses at $35 billion to $45 billion, Verisk and other modelers produced somewhat lower ranges, and Moody’s RMS offered still different assessments as the events were unfolding. Swiss Re and other reinsurers reported multibillion‑dollar market impacts while framing their own exposures as smaller and manageable. (businesswire.com)
“The L.A. events exposed model and accumulation blind spots,” said one reinsurance executive in a recent investor call, describing how complex urban exposures and high‑value dwellings amplified losses beyond many pre‑event expectations. Swiss Re, speaking in its 2024 and early‑2025 releases, said the firm’s own losses from the fires were relatively modest but that industry‑level estimates ran into tens of billions of dollars — and that the events would be folded into updated loss assumptions at renewals. (finanzwire.com)
Why models are being rewritten
Model vendors and insurers have publicly acknowledged limits in earlier hazard and vulnerability treatments and have accelerated upgrades to capture new patterns. Moody’s RMS, for example, released an updated North America Wildfire HD model (v2.0) and has been rolling out high‑definition severe convective storm models to better represent tornado, hail and straight‑line wind risk at fine spatial scales; the release notes say SCS perils have “recently surpassed hurricanes as the leading cause of insured losses in North America” and describe improvements in temporal modelling and vulnerability calibration. Verisk/CoreLogic and other analytics groups likewise revised fuel datasets, smoke and evacuation cost assumptions, and exposed value granularity. Those model shifts drive higher estimated probable‑maximum‑loss (PML) metrics for some portfolios, forcing insurers to re‑price, prune accumulations, or buy more reinsurance or alternative capacity. (developer.rms.com)
“Model refinement is not academic — it changes capital allocation and underwriting limits,” said a catastrophe‑model specialist at a global insurer. “When a vendor tightens the vulnerability curve or adds location‑level fuel and mitigation attributes, your AEL [accumulation exposure limit] and reinsurance purchase decisions change overnight.” Zurich Insurance’s annual reporting documented that model scope and granularity extensions — for example in hail and flood models in Europe — led to measurable changes in their modeled AELs and in how they steer portfolios. (financialreports.eu)
Underwriting, pricing and the renewal cycle
The model updates and recent loss experience fed directly into the 2025 treaty‑renewal rounds and primary‑market pricing. Swiss Re said it achieved price increases in the January 2025 renewals and that updated loss model assumptions increased loss expectations by roughly 4.6% at the mid‑year renewals, prompting selective pruning of exposures in casualty and other lines. Reinsurers reported stronger pricing in areas with heightened modelled exposures; brokers and cedents told investors that market appetite for protection shifted meaningfully in the months after the large wildfires and SCS events. (swissre.com)
But results varied across markets. The U.S. property‑and‑casualty (P&C) sector posted one of its best aggregated underwriting years in 2024, with S&P Global Market Intelligence reporting a net combined ratio of about 96.5% for the U.S. industry — its best since 2013 — reflecting favorable personal‑lines results. At the same time, global reinsurance and specialty markets have shown rising combined ratios in pockets hard hit by nat‑cat losses, with Lloyd’s of London and several European players flagging elevated catastrophe claims that pushed combined ratios higher in reporting periods. The mixed performance underscores the heterogenous nature of natural‑catastrophe risk and the speed with which a single large event can tilt returns for reinsurers and primary carriers exposed to particular regions or lines. (spglobal.com)
Investment responses: chasing yield and diversifying risk transfer
As underwriting profitability faced erosion from heavier catastrophe losses and higher repair costs, insurers’ investment teams sought higher yield and new forms of capacity. Surveys and market reports show a clear pivot: insurers in 2025 signaled intent to expand allocations to private credit, private debt and other private assets, while also increasing use of insurance‑linked securities (ILS) and catastrophe bonds as alternative reinsurance capital. Goldman Sachs Asset Management’s 2025 Global Insurance Survey found that 58% of surveyed insurance CIOs and CFOs planned to increase allocations to private credit over the next 12 months, and 35% were less likely to increase portfolio duration — a sign of caution on interest‑rate exposure even as firms hunt for returns. At the same time, the ILS market expanded rapidly: Aon reported record catastrophe‑bond issuance and a mid‑2025 alternative‑capital stock that approached new highs, reflecting insurer demand for collateralized, multi‑year risk transfer capacity. (am.gs.com)
“Private credit and ILS are attractive because they offer yield and uncorrelated returns relative to equity markets, and catastrophe bonds can effectively extend reinsurance capacity,” said Mike Siegel, Global Head of Insurance Asset Management and Liquidity Solutions at Goldman Sachs Asset Management, in the GSAM survey materials. But he and other asset managers cautioned insurers to balance higher yields against liquidity, valuation opacity and concentration risks in private markets. (am.gs.com)
The ILS market’s growth has not only provided cedents with additional capacity but also shifted some risk to capital‑market investors. Aon’s mid‑2025 reporting documented unprecedented cat‑bond issuance volumes and growing insurer participation as sponsors — a development that both supplements reinsurance supply and potentially changes how insurers manage peak‑risk capital. Market participants emphasize that while cat bonds can smooth capacity cycles, they do not remove underwriting discipline; pricing still reflects updated hazard and vulnerability inputs. (globalreinsurance.com)
Model uncertainty, capital math and balance‑sheet consequences
Upgraded models often produce higher modeled AALs (average annual losses) and PMLs for particular portfolios. For reinsurers and insurance companies that use modeled PMLs in internal capital allocation and in negotiating reinsurance, those higher numbers can translate into more costly capital requirements, pressure on return on equity targets, and higher reinsurance spend. Swiss Re and others said their underwriting and capital positions remained robust in public reports, but they also explicitly linked renewed pricing and portfolio pruning to updated model assumptions and to a “prudent view” on inflation and exposure growth. (swissre.com)
Regulators and rating agencies are watching. Higher catastrophe loadings and model changes can affect solvency metrics and rating agency assessments, particularly for smaller carriers with concentrated exposures or thin balance sheets. Industry analysts say that accurate, transparent modelling — and clear disclosure around model choice, versioning and sensitivity — are essential to avoid surprise capital hits and to allow markets to price risk properly. (developer.rms.com)
Operational and strategic shifts inside insurers
Beyond pricing and investments, insurers are changing product design, appetite and portfolio steering. Several large carriers reported selective non‑renewals or higher deductibles in high‑risk ZIP codes, more aggressive catastrophe accumulation management, and increased investment in loss‑mitigation engineering for commercial clients (for example, wildfire hardening and hail‑resistant building specifications). Zurich’s reporting described richer exposure‑level attributes in its modelling and a push to scale “climate solutions” and impact investments while managing underwriting exposures. Those strategic pivots are consistent with broader industry aims to protect capital while maintaining market presence in at‑risk geographies. (financialreports.eu)
Climate science and the longer season
Climate researchers and national agencies have documented trends that underpin the industry’s adjustments: warming temperatures, earlier spring snowmelt in the West, longer dry spells and more days with conditions conducive to fire have extended wildfire seasons in many regions, and atmospheric dynamics are altering convective‑storm exposures. A Nature Communications analysis of the record‑breaking 2023 Canadian fire season described an extension of the fire season and linked the pattern to warming and extremes; climate‑science summaries and U.S. assessments likewise connect a longer window of fire danger and changing storm behavior to human‑driven climate influences. Insurers and model vendors cite these observations when they justify model re‑calibration and the need to treat wildfire and SCS perils as less predictable and more damaging than past data implied. (nature.com)
Tradeoffs and the path ahead
The industry faces a policy set of tradeoffs. More conservative underwriting and higher reinsurance buys protect solvency but can reduce premium volume and market share. A shift into private assets and ILS can boost returns and capital availability but introduces liquidity and valuation risks and requires different governance and risk‑management capabilities. Model upgrades reduce some uncertainty but can simultaneously raise estimated losses, creating a near‑term profitability squeeze. These dynamics help explain why reinsurers like Swiss Re and others publicly emphasized disciplined underwriting, portfolio steering and the role of alternative capital in mid‑2025 commentary. (swissre.com)
Industry voices
“Insurers and reinsurers cannot treat these events as once‑in‑a‑decade outliers,” Andreas Berger, CEO of Swiss Re, said in the company’s 2024‑2025 communications. “We are adjusting pricing, portfolios and capital deployment to ensure we remain resilient and continue to support clients.” Model vendors argue that improved hazard representations, coupled with richer exposure data, will let underwriters make better, faster accumulation decisions. Asset managers stress disciplined portfolio construction as insurers increase allocations to privates and ILS. (swissre.com)
What policyholders and officials should expect
For homeowners and commercial policyholders, the near‑term consequences are already visible in availability and price: higher deductibles, more restrictive coverage terms in high‑hazard zones, and in some areas, market exits by certain carriers. Public officials and regulators are confronting related issues — affordability, mitigation incentives and the need for better data on building vulnerability and community resiliency. Industry‑wide, executives say that balancing economic access to insurance while pricing risk accurately is a critical test for the sector in a warming world. (claimsjournal.com)
Bottom line
A succession of high‑cost events in 2024–2025 forced a reckoning across the insurance value chain: model vendors issued technical upgrades that raised some carriers’ loss expectations; underwriters tightened exposures and sought higher pricing at renewals; and investment teams pivoted toward private credit and ILS to support returns and extend capacity. The changes reflect the reality that wildfire, severe convective storms and other climate‑linked perils are expanding in season and scope, and that insurers must adjust models, products and portfolios accordingly. How effectively the industry balances underwriting discipline, capital efficiency and the public interest in affordable coverage will shape resilience to natural disasters in the years ahead. (developer.rms.com)
Sources: Swiss Re, company filings and press releases; Moody’s RMS developer release notes and model changelog; CoreLogic, Verisk and other catastrophe‑analytics releases on the 2025 California fires; Goldman Sachs Asset Management 2025 Global Insurance Survey; Aon ILS Annual Report and market commentary; S&P Global Market Intelligence; Nature Communications wildfire analysis; Financial Times reporting on Lloyd’s of London and market impacts. (swissre.com)
(Reporting contributed by industry analysts and model‑vendor statements cited above.)