Property rates are falling across commercial lines while casualty costs continue to climb - a split that is forcing risk and finance leaders to treat the two halves of their insurance programme as separate analytical problems. Aon plc has launched two consulting-led tools built around that divide: the property risk diagnostic and the casualty risk diagnostic, designed to give organisations an evidence-based view of their exposure in each class and where to act first.
The launch is the latest step in Aon's effort to extend its role beyond placement into ongoing advisory. The property risk diagnostic and casualty risk diagnostic follow the broker's AI risk diagnostic, released in July to help organisations assess AI governance maturity and risk exposure, as well as an existing suite of risk analyser tools covering property, casualty, cyber, and directors and officers liability.
The Alliant Insurance Services 2026 Mid-Year Insurance Marketplace Insights and Observations Report, which drew on data from specialised broking teams across more than a dozen industry sectors, shows the breadth of that split. Some real estate insureds have recorded double-digit property rate reductions for the second or third consecutive renewal.
Casualty lines are moving the other way. Auto liability rates are running between 7% and 25%, umbrella liability between 10% and 20%, with social inflation and nuclear verdicts showing no sign of easing. That divergence is exactly the environment in which separating property and casualty risk analysis becomes a practical necessity rather than an analytical preference.
The property risk diagnostic, delivered by Aon Global Risk Consulting engineers, combines modelled and historic loss estimates across natural catastrophe and non-catastrophe property risks. It allows organisations to compare sites and hazards, test resilience options side by side, and build a business case for investment. The resulting roadmap can be refreshed over time to evidence year-on-year improvement, which has direct relevance to renewal conversations, where underwriters increasingly reward clients who can demonstrate documented risk improvement with more competitive terms.
The casualty risk diagnostic addresses a different but related pressure. Total cost of risk (TCOR), the aggregate of premiums, retained losses, and risk management administration costs, has become a board-level metric as casualty claims costs rise and margins narrow. The tool analyses client claims data across auto liability, general liability, and workers' compensation, benchmarking performance against Aon's proprietary peer database on a quarterly basis.
It is initially available to clients in North America, with broader international availability planned for 2027.
A tool that updates TCOR tracking every three months, rather than at annual renewal, changes the nature of the broker-client conversation. It shifts from a placement transaction to an ongoing performance review, one where brokers can point to measurable progress, or flag deteriorating trends before they harden at renewal.
"Clients are asking a sharper question than a few years ago: not just what their risk is, but what to do about it and what it is worth," said Christian Hoffman, chief executive of commercial risk at Aon.
"Analytics only create value when they inform what a client does next," added Richard Waterer, Aon's global risk consulting leader.
The two diagnostics reflect a broader competitive dynamic in commercial broking. As pricing transparency increases and data literacy among risk buyers grows, clients expect their brokers to do more than negotiate premium. They expect structured, evidence-based counsel on risk mitigation and programme design.
Aon is not alone in moving in this direction. Marsh launched its AI-powered risk companion suite in April, including a renewal companion tool for real-time modelling of retentions, limits, and deductibles. The pattern across the major brokers points to a structural shift in what commercial clients expect from their advisers, and raises the bar for what structured risk analysis looks like at renewal.
