Skip to main content


More than software. A solution.

Over 25 years of actuarial and insurance software experience at your fingertips.

Arius is Milliman’s award-winning property & casualty reserve analysis solution.

Arius® is a complete solution for analyzing unpaid claims liabilities, combining our industry-leading stochastic modeling tools with a robust suite of deterministic reserving tools and actuarial methods.

Property and casualty actuaries now have the tools you need to really understand your business, all at your fingertips. The result is a more efficient actuarial analysis process and a deeper understanding of the underlying insurance exposure, for more informed business decisions.

Desktop insurance reserve analysis


Powerful deterministic tools

  • Examine your existing actuarial data in many new ways – Arius provides hundreds of exhibits, methods, and management reports, all pre-built and ready to use.
  • A full range of reserving methods address virtually any specialized need.
  • Easily build your own actuarial methods and reports.
  • Share your customized methods and reports with other analyses and other users.
  • Extensive graphics and diagnostic exhibits provide instant access to new insights from your current data.

A rich modeling solution

  • Complete distributions of possible outcomes.
  • Estimates of the mean and expected losses by percentile.
  • VaR and TVaR estimates.
  • Loss ratios, cash flows, and run-offs by percentile.
  • Simulate multiple segments together, along with correlation.

Arius works like you work

  • The system’s workflow is configurable.
  • Set Arius up to mirror the processes your reserving department currently uses.
  • Startup time is minimized.
  • Your team will recognize value from the software almost immediately.

Consistency streamlines your process

  • Streamline your review time and consolidation with Arius’ consistent reporting.
  • Reviewers know which calculations to expect and exactly where to look for specific information in each project.
  • Easily share new or customized reports among users and across projects.

Reliability helps managers be more efficient

  • Arius eliminates most of your current spreadsheet tech checking – a huge time savings for your team.
  • The system tightly controls the flow of all information for a seamless actuarial risk assessment.
  • Results from one calculation instantly update all related parts of the analysis.
  • All calculations are extensively tested by Milliman’s team of software and actuarial professionals.

Extensibility when needed

  • An application programming interface (API) helps you easily exchange data between Arius and spreadsheets.
  • Use Visual Basic or VBA to share data, factors, and selections with spreadsheet-based exhibits.
  • Eliminate the risks of copying and pasting.

Arius Enterprise: A better reserving process starts here

Arius Enterprise® builds on the Arius toolset to help you manage your overall reserving and reporting process, increase efficiency, and improve the accuracy of your reserve estimates.

With a powerful database, sophisticated analysis and reporting, automation, and rock-solid performance and security, your entire P&C reserve analysis process just got a lot better.


Arius Enterprise features

Arius Enterprise is an actuarial platform that streamlines your entire P&C reserve analysis process. It gives you:


The Arius database is custom designed to meet your company’s unique analysis style and reporting requirements and gives you complete control of your data.

Healthcare Data Analytics Benefits Analytics Icon

Robust analysis tools

Arius Enterprise provides your users with direct access to Arius, the industry’s leading reserve analysis tool set.


Arius does much of the mundane work of P&C reserve analysis for you, so you can spend your valuable time where it matters most.


Analysis templates

Consistent analysis across your department adds efficiency to your overall process.


While you do most of your analysis down in the trenches, we understand that a lot of additional work goes into summarizing your results for final reporting.


Project Management

Arius Enterprise helps you keep track of the status of all analysis projects throughout the reserving team.


Modern technology

The Microsoft Azure Cloud makes everything easier and more secure.


We know that managing the security over your reserving processes is important to you. It is to us, too.

Arius Enterprise benefits

Arius Enterprise combines immediate access to all your data, superior tools to analyze and report on your results, and systems to automate much of the routine work in your regular actuarial analysis process. You get analyses that are efficient, consistent, and accurate. You can be more confident in your results and add more value to your organization.

Short time to value

  • Your users will be enjoying the benefits of Arius Enterprise in a matter of weeks.
  • Similar in-house development can take years and cost substantially more.
  • We handle most of the implementation, working closely with your team.
  • We will help you test the solution in your environment and we will train your professionals.
  • With Arius Enterprise, your team also gets the benefit of many other companies’ ideas and input.

Process redesign consulting

Our specialists will work with you to:

  • Understand your overall department goals and challenges
  • Review your current processes, workbooks, approaches, and resulting reports
  • Make recommendations based on best practices at similar insurers already benefiting from the system
  • Help implement a more efficient and informative overall reserving work stream

Arius analysis toolset

Arius Enterprise includes one of the most widely used actuarial analysis systems in the world.

  • Arius is a complete framework for your entire insurance reserve analysis.
  • It offers over 40 deterministic reserving methods, more than 10 stochastic reserving models, and more than 200 exhibits and reports, already defined and ready to use.
  • Arius provides sophisticated analyses without formulas or programming hassles.

Advanced machine learning

The Arius Advanced Analytics module uses innovative data science and modeling techniques to provide new insights and help you make more informed decisions.

  • More than stand-alone models, it is actuarial software that integrates modeling capabilities into the automated reserving workstream, for more actionable information without more work.
  • These modeling solutions are developed in collaboration with Microsoft’s Azure Machine Learning technology and data science teams.
  • Advanced Analytics relies on transparent models that your team can enhance, modify, and expand over time.

Arius Enterprise powered by Microsoft Azure Data Explorer

As the volume and complexity of its clients’ data grew, the Arius team joined forces with Microsoft to expand the system’s database capabilities.

Arius Enterprise wins InsuranceERM Award two years in a row

Winner of the 2021 and 2020 InsuranceERM Awards - Americas "Cloud Technology Solution of the Year," Arius Enterprise joins the leaders in enterprise risk management for another year.

Triangles on Demand: Take control of your reserving data

With TOD, you’ll save hours every quarter summarizing and reconciling claim, expense, and other insurance data. TOD quickly rolls up hundreds of millions of records into triangles of any size and level of detail. Simply request your specific data sets from within Arius and all the resulting triangles appear in the system ready for you to use.


Triangles on Demand benefits

Get the information you need when you need it

  • Get direct access to whatever data you need whenever you’re ready, delivered directly to your desktop.
  • Get any new grouping you want—for example, to take a closer look at a specific or challenging issue.
  • Get triangles by state or coverage rather than your normal feed of country-wide or sub-line triangles.
  • Look at data at specific claim limits to help with strategic planning.

IT: Keep the actuaries happy without sacrificing control

  • Actuaries can now generate their own roll-ups or detailed breakdowns directly from the source components.
  • Reconciling totals are automatic and instantaneous, assuring reliable numbers without IT’s extensive involvement.
  • Commercial-grade security, auditability, and effective use of the Microsoft Azure cloud help you keep the company and your users safe.

Milliman expertise

Milliman’s team of experts will work closely with both your actuarial and IT professionals to:

  • Help you take best advantage of TOD’s power and capabilities
  • Configure the system to work with your other in-house systems
  • Ensure all systems are reliably communicating to get you that important data as directly and efficiently as possible

Triangles on Demand in action


Triangles on Demand demonstration

See how you can save hours every period rolling up, preparing, and reconciling loss, expense and claim details to meet your increasingly tight deadlines.

Watch the video

Contact an Arius expert

We’re passionate about partnering with people and working with new solutions to solve complex problems. Let’s chat about what’s going on with your business and how we can help.

Contact an Arius expert

We’re passionate about partnering with people and working with new solutions to solve complex problems. Let’s chat about what’s going on with your business and how we can help.

popup image