Re-platforming our asset modelling solution

Summertime is Broadstone’s cloud-based asset modelling solution, built to tackle the complex Solvency II SCR market stress calculations faced by insurance investment managers. It is used by our actuarial team and external clients to check asset data, model market SCR, analyse results and test a range of portfolio scenarios.

An earlier version of the engine ran on a legacy platform and, while reliable, had reached its limits. Organising the data and inputs was time-consuming, the front-end was cumbersome, and results came out in a clunky Excel format — making them slow to interrogate and hard to extend with the richer analytics and scenario work our clients increasingly needed.

We set out to:

• Replatform the engine into Python, giving us a modern, maintainable and extensible codebase.
• Add new capability — analytics, scenario generation and scenario analysis — that the legacy engine could not support.
• Streamline the end-to-end process, cutting out manual steps and making the whole workflow faster and easier to use.
• Host the engine so it could be accessed externally by clients as well as our own team.

We rebuilt Summertime from the ground up in Python, redesigning the workflow around the people who use it.

The rebuild added capabilities the legacy engine couldn’t offer:

• Analytics — dynamic, interactive charts and heat maps that visualise credit quality and market value, highlight concentration risk, and break results down by currency, spread risk, concentration and counterparty risk, all interrogable line by line.
• Scenario generation — adjusting the asset mix by asset class, risk level or duration, and applying additional interest rate stresses, in a few clicks and without manual data manipulation.
• Scenario analysis — testing portfolios across a range of scenarios to understand the impact on market SCR and results.

The end-to-end process was streamlined to remove the manual steps that had made the legacy tool slow to run. Summertime is now cloud-hosted, giving secure access to authorised users — our actuarial team and external clients alike — from anywhere, underpinned by our ISO 27001-certified information security controls.

To give users confidence in the new engine, results were validated against the legacy version through full reconciliation before go-live.

Asset calculations that once meant waiting now return in a few minutes, and users can run far more scenarios and richer analytics than the legacy tool ever allowed. The cumbersome front-end and clunky Excel outputs are gone, replaced by a clean, interactive, cloud-based application.

Because Summertime is now accessible externally, insurance investment managers and actuarial teams can interrogate their asset holdings and run their own scenarios directly — speeding up year-end processing, supporting more informed investment decisions, and freeing our specialists to focus on insight rather than process. The new architecture also positions Summertime for further analytics and scenario capability as client needs evolve.