Best Insurance Reserving Software in 2026

On this page (10)

1. The shortlist
2. TL;DR
3. Different tools solve different parts of the reserving problem
4. The 5 best insurance reserving software tools for P&C actuaries
5. How do these reserving tools compare side by side?
6. How is reserving software different from pricing software?
7. Which tool fits your team?
8. Conclusion: pick the governance you need, then the methods
9. How we chose
10. FAQs

What is the best insurance reserving software?

Updated Nov 3, 2026 · ranked by fitWTW ResQ ranks first of the 5 tools we compared: best for enterprise reserving teams that want governance and scripting. Pricing is by quote. Akur8 and Insureware ICRFS follow.

TL;DR

• Reserving software helps actuaries estimate what an insurer still owes on claims already incurred, including IBNR, by building loss triangles and running methods such as chain ladder and Bornhuetter-Ferguson.
• WTW ResQ is the broadest enterprise pick: WTW says more than 500 companies use it, every feature can be scripted, and it adds stochastic and IFRS 17 options.
• Akur8 Reserving is the former Milliman Arius, which Akur8 bought in September 2024. It suits teams that want pricing and reserving from one vendor.
• Insureware ICRFS fits long-tail lines where calendar-year trends and social inflation matter; addactis Reserving is a guided SaaS app tied to Solvency II and IFRS 17 work.
• Only the open-source chainladder Python package has a public price, and it's free. The four commercial vendors quote by sales.

At each quarter close, a reserving team has to say how much the insurer still owes on claims it has already taken on, including the ones nobody has reported yet. The work means rolling claims data forward into development triangles, running several methods, picking an answer for each segment and defending it to auditors and regulators. Comparing the software is hard because vendors describe the same methods in different terms, none of the commercial products publishes a price, and Milliman sold its Arius reserving product to Akur8 in 2024.

Different tools solve different parts of the reserving problem

Shape	What it focuses on	Tools in this list
Enterprise reserving platform	Triangles, standard methods, selections, governance and automation for large teams	WTW ResQ, Akur8 Reserving (Arius)
Statistical trend modeling	Models trends in development, accident and calendar periods instead of link ratios	Insureware ICRFS
Guided SaaS reserving app	Step-by-step reserving connected to IFRS 17 and capital modeling	addactis Reserving
Open-source library	Reserving methods you call from your own Python code	chainladder

Enterprise platforms fit insurers and reinsurers with many segments, reviewers and sign-off steps. Trend modeling fits long-tail liability books where inflation and calendar-year effects drive the answer. A guided SaaS app fits smaller teams moving off spreadsheets, and an open-source library fits actuaries who already work in Python and want full control of the code.

The 5 best insurance reserving software tools for P&C actuaries

1. WTW ResQ: Best for enterprise reserving teams that want governance and scripting

Quote onlyFull profile →Visit site of WTW ResQ (opens in a new tab) ↗

Best for: P&C insurers, reinsurers and Lloyd's managing agents with large reserving teams that need audit trails, automation and stochastic ranges.

WTW ResQ is WTW’s loss reserving software for P&C insurance and reinsurance. WTW says it keeps data, methods and selections in one central repository, rolls data forward to each evaluation and builds the triangles and reserving segments for you. Its success stories include a Lloyd’s managing agent and a global multinational carrier, and WTW also offers ResQ Cloud as a fully managed SaaS option. WTW sells Radar for pricing.

Key functionalities

• Pre-built, pre-tested actuarial methods with graphical diagnostics
• Machine-led parameter selection for the built-in aggregate methods
• Roll-forward to each evaluation and automatic triangle building
• Role-based access, review workflow and an audit log of every change
• Code access to every feature, plus WTW’s Unify platform for wider automation
• Stochastic add-on for reserve ranges, and ResQ Financial Reporter for IFRS 17

Pros:

• Used by more than 500 companies, according to WTW
• Every feature and button is accessible by code, with role-based access and a full audit log
• Stochastic add-on, IFRS 17 reporter and Sarbanes-Oxley and Solvency II configurations

Cons:

• Pricing not published
• Stochastic ranges come as an add-on package, and IFRS 17 reporting is a separate product, ResQ Financial Reporter
• WTW's ResQ page doesn't list security certifications

Pricing: Not published; quoted by sales.

Verdict: The broadest fit for large reserving teams that want one governed system of record. Smaller teams should check whether they need the scripting and add-ons before paying for them.

2. Akur8: Best for teams that want reserving and pricing from one vendor

Quote only · SOC 2 Type IIFull profile →Visit site of Akur8 (opens in a new tab) ↗

Best for: P&C insurers, particularly in the US and Canada where Arius built its client base, and Akur8 Pricing customers who want both actuarial teams on one vendor.

Akur8 bought Arius from Milliman in September 2024. At the time, Akur8 said Arius had 150 insurance and consulting clients and over 1,500 users, and that more than a third of those clients were top-tier carriers in the US and Canada. It now sells the product line as Akur8 Reserving and says actuaries can start using it in hours. The Arius product pages, once on Milliman’s site, now sit on Akur8’s.

Key functionalities

• Deterministic methods and stochastic reserving models, with calculations in real time
• Customizable reports and exhibits that the system manages
• Analysis templates for consistent work across users
• Automated file preparation, new-period setup, roll-forwards and actual-vs-expected analysis (Arius Enterprise)
• Summary reporting database with API connections to other systems
• Access rights, audit trails and project locking after sign-off

Pros:

• Three solution sets: Arius, Arius Enterprise (cloud) and Triangles on Demand
• Arius Enterprise adds project management, sign-off locking, audit trails and Power BI visualization
• Same vendor as Akur8 Pricing, and Akur8 lists SOC 2 Type II and ISO 27001

Cons:

• Pricing not published
• Akur8 described a fully integrated pricing and reserving platform as its goal at the acquisition; ask what is connected today
• The '4x faster' figure on its page is Akur8's own claim

Pricing: Not published; quoted by sales.

Verdict: The natural pick for current Arius users and for insurers already buying Akur8 Pricing. Teams with no Akur8 relationship should compare it directly with ResQ.

3. Insureware ICRFS: Best for long-tail lines and calendar-year trend modeling

Quote onlyFull profile →Visit site of Insureware ICRFS (opens in a new tab) ↗

Best for: Actuaries reserving long-tail liability lines who need to measure social inflation and calendar-year trends across lines.

Insureware ICRFS is built on what Insureware calls the Probabilistic Trend Family (PTF) and Multiple Probabilistic Trend Family (MPTF) modeling frameworks. Insureware argues that link ratios can’t measure calendar-year or social inflation trends, and positions ICRFS as one company-wide model that actuaries and executives can question in real time. Insureware says it covers reserving, pricing and risk capital.

Key functionalities

• Modeling wizard and optimization to find a parsimonious model for each line
• Calendar-year trend, social inflation and law-reform impact measurement
• Volatility correlations between lines and segments
• Risk metrics for ORSA, Solvency II and IFRS 17
• Reserves net of reinsurance, and pricing of risk transfers such as ADCs and LPTs
• ELRF product family, including a Best’s Schedule P version

Pros:

• Models trends in development, accident and calendar periods, plus the volatility around them, per Insureware
• One composite model across lines of business and segments
• Still includes Mack, bootstrap and chain ladder ratios

Cons:

• A different modeling approach from link ratios, so teams need time to learn it
• Pricing not published
• Insureware's site says little about deployment or security

Pricing: Not published; quoted by sales.

Verdict: Worth a look when long-tail trends drive your reserves and link ratios keep surprising you. Teams that want a standard triangle workflow will find ResQ or Arius more familiar.

4. addactis Reserving: Best for a guided SaaS workflow tied to Solvency II and IFRS 17

Quote onlyFull profile →Visit site of addactis Reserving (opens in a new tab) ↗

Best for: Non-life insurers moving off spreadsheets that want a step-by-step SaaS reserving tool connected to IFRS 17 and capital modeling.

addactis Reserving is a SaaS application that covers reserving studies, claims analysis, cash-flow projections and regulatory compliance. addactis says more than 2,200 users trust its solution, and the app guides users step by step with templates.

Key functionalities

• Paid or incurred triangles, underwriting or accounting origin years, and inflation vectors
• Scenario testing of reserving assumptions
• Volatility analysis across methods and assumptions
• Comments, change tracking and exportable audit trails
• Part of the addactis platform with IFRS 17, capital modeling and pricing

Pros:

• Chain ladder, Bornhuetter-Ferguson, average cost, loss ratio and Mack bootstrap methods
• Replicates existing Excel-based methods inside the app
• Connects to addactis IFRS 17, capital modeling and pricing applications

Cons:

• Pricing not published
• Its reserving page cites a Spanish customer and French market research, so ask for references in your market
• addactis's page doesn't list security certifications

Pricing: Not published; quoted by sales.

Verdict: A practical choice for teams that want a guided tool and already use, or plan to use, addactis for IFRS 17 or Solvency II. Large reserving departments may want the deeper scripting of ResQ.

5. chainladder (Python): Best free option for actuaries who work in Python

Free to startFull profile →Visit site of chainladder (Python) (opens in a new tab) ↗

Best for: Actuaries comfortable in Python who want free reserving methods they can read, test and extend.

chainladder is a Python package for property and casualty loss reserving. Its maintainers say it covers triangle data manipulation, link ratio calculations and IBNR estimates with both deterministic and stochastic models. The R equivalent, ChainLadder on CRAN, includes methods to estimate the claims development result required under Solvency II.

Key functionalities

• Triangle data structures and manipulation
• Link ratio calculations
• Deterministic and stochastic IBNR models
• Estimators that work like scikit-learn models
• Install with pip or conda-forge

Pros:

• Free under the Mozilla Public License 2.0
• Hosted in the Casualty Actuarial Society's official GitHub organization
• Syntax follows pandas and scikit-learn; R users have the separate ChainLadder package

Cons:

• No vendor support, user permissions or sign-off workflow
• Maintained by volunteers
• Your team builds reporting, governance and data pipelines itself

Pricing: Free and open source (source).

Verdict: A strong base for teams that want reserving in code they control, or a second opinion next to a commercial system. Teams that need audit-ready sign-off out of the box should buy one of the four products above.

How do these reserving tools compare side by side?

How is reserving software different from pricing software?

Reserving looks back at claims that have already happened and estimates what’s left to pay. Pricing looks forward and sets the premium for policies the insurer hasn’t written yet, using risk models and a rating engine. Both start from the same claims history, so a few vendors sell both: Akur8 pairs Akur8 Pricing with Akur8 Reserving, and WTW pairs Radar with ResQ. For the pricing side, see insurance rating and pricing software.

Which tool fits your team?

• You run a large reserving function with many segments, reviewers and an IFRS 17 or Solvency II deadline: WTW ResQ.
• You already use Arius, or you buy Akur8 Pricing and want one vendor: Akur8 Reserving.
• Your reserves are dominated by long-tail liability and social inflation: Insureware ICRFS.
• You want a guided SaaS tool and already use addactis for IFRS 17 or capital modeling: addactis Reserving.
• Your actuaries code in Python and want free, inspectable methods: chainladder.

Conclusion: pick the governance you need, then the methods

All five tools run the standard methods, so the choice usually comes down to how much review, automation and reporting sits around them. Ask each vendor to load one of your own triangles, show how a selection is locked after sign-off, and say whether the stochastic and IFRS 17 features cost extra.

How did we choose these tools?

The order is our editorial judgment of fit for the job this guide covers, not a test score. Prices appear only where the vendor publishes them or a cited source reports them; otherwise we name the pricing model and mark it "Quote only." SOC 2 status comes from each vendor's trust or security pages. These profiles are desk research: we have not run the products on real files. Full methodology.

FAQs

What is insurance reserving software?

Insurance reserving software is what reserving actuaries use to estimate the money an insurer still owes on claims from policies already written, including claims incurred but not yet reported (IBNR). It organizes claims data into development triangles, applies methods such as chain ladder, Bornhuetter-Ferguson and Mack bootstrap, and records the actuary's selections with an audit trail for financial and regulatory reporting.

What is the best insurance reserving software?

For a large P&C insurer or reinsurer that wants a governed, scriptable system, WTW ResQ is the broadest option; WTW says more than 500 companies use it. Akur8 Reserving (Arius) fits teams that want pricing and reserving from one vendor. Insureware ICRFS fits long-tail lines where calendar-year trends matter, addactis Reserving fits teams that want a guided SaaS workflow, and the free chainladder package fits actuaries who work in Python.

What happened to Milliman Arius?

Akur8 acquired Arius from Milliman, announcing the deal on September 9, 2024, and Milliman increased its equity stake in Akur8 as part of the transaction. Arius is now sold as part of Akur8 Reserving, in three solution sets: Arius, Arius Enterprise and Triangles on Demand.

Is there free reserving software?

Yes. chainladder is an open-source Python package hosted by the Casualty Actuarial Society, released under the Mozilla Public License 2.0, with triangle tools, link ratios and deterministic and stochastic IBNR models. R users can use the ChainLadder package on CRAN. Neither comes with vendor support or a sign-off workflow.

What is the difference between reserving software and pricing software?

Reserving software estimates liabilities on claims that have already happened. Pricing software sets premiums for policies not yet written, using models such as GLMs and a rating engine to apply the rates. Akur8 and WTW sell both kinds; see insurance rating and pricing software for the pricing side.

Does reserving software support IFRS 17 and Solvency II?

Several products address them. WTW sells ResQ Financial Reporter for IFRS 17 and offers ResQ configurations for Sarbanes-Oxley and Solvency II. Insureware lists ORSA, Solvency II and IFRS 17 risk metrics among ICRFS uses. addactis connects its Reserving app to its own IFRS 17 and capital modeling applications.

How much does insurance reserving software cost?

WTW, Akur8, Insureware and addactis don't publish prices; all four quote by sales. The chainladder Python package and the ChainLadder R package are free, though your team carries the cost of building governance, reporting and data pipelines around them.

Can reserving software replace spreadsheets?

That is the main pitch from most vendors. Akur8 says Arius replaces spreadsheet-based analysis, WTW says ResQ keeps data, methods and selections in one repository instead of a network of spreadsheets, and addactis lets teams replicate existing Excel methods inside its app before automating them.