An insurer can spread its policies among thousands of customers while still depending on a remarkably small number of outcomes. A single catastrophic loss, a large insured location, a connected set of borrowers or a reinsurance counterparty can concentrate risk on one balance sheet. Canadian prudential rules recognize that the number of policies written is a poor substitute for understanding how much the institution could lose when exposures converge.
The Office of the Superintendent of Financial Institutions has scheduled a final version of Guideline B-2, Large Exposure Limits, for property and casualty and life and fraternal insurers on November 19, 2026. That date appears in OSFI's September 3 policy planning letter and is a planned publication date rather than an effective date. As of November 8, the final version is still forthcoming. Insurers therefore need to separate today's applicable guidance from any requirements that could be announced later this month.
Under the property and casualty version of B-2 effective January 1, 2025, federally regulated insurers are expected to maintain a gross underwriting limit policy consistent with their risk appetite. The policy should define a single insurance exposure by class, set limits for gross risk and undergo senior management review at least annually. An insurer should estimate the maximum loss using reasonable, supportable and forward looking information rather than relying only on the historical probability that the event will happen.
The guideline offers concrete examples. Property policies may need to be aggregated at one location, credit insurance exposures may depend on a single buyer or connected group, and surety bonds can accumulate around one contractor. A company insuring several buildings in the same complex can't safely treat each policy as an entirely independent event. The same issue arises when related businesses appear under different names but share the financial fortunes of one enterprise.
Risk can also be concentrated outside the underlying insured event. The existing guideline examines the amount an insurer retains after reinsurance together with the consequences of an unregistered reinsurance counterparty failing when that large claim occurs. A policy portfolio may appear well protected until the institution asks whether its recovery is collectible when the reinsurer is under stress. Investment concentration presents a related but distinct exposure that deserves its own oversight.
There are reasons for caution when interpreting the coming revision. OSFI also published a separate B-2 consultation in May 2026 concerning large exposures at banks and certain trust and loan companies. That banking proposal discusses Tier 1 capital limits and implementation in 2027 or 2028. The banking thresholds can't simply be imported into an article about insurer risk limits. Regulators use the same guideline number for different institutional sectors, and precision about scope matters.
A new supervisory guideline also has to be distinguished from an insurance contract with a customer. The regulator's expectations concern the insurer's capacity to manage its risks and remain financially sound. They don't automatically rewrite an individual policy, create a new exclusion or determine whether a particular insured has coverage. Claim interpretation still turns on the policy wording and the applicable law.
Boards should be able to see where significant risks converge across insured locations, assumed business, counterparties and investments. Internal reporting should explain maximum potential losses, the assumptions behind aggregation, available capital and the conditions under which reinsurance protection could fail. Those questions may be uncomfortable when a fast growing business line is profitable, but the purpose of concentration analysis is to discover whether profits depend on a narrow set of favourable outcomes.
The November 19 date is therefore worth watching without assuming the final guideline's content in advance. OSFI's scheduled release could clarify requirements and transition arrangements, and timelines can change. For now, the existing rules already make a serious demand of federally regulated property and casualty insurers. They must understand the exposure they have accumulated rather than accepting a diverse customer list as proof that the risks themselves are diverse.
Sources
OSFI, September 3, 2026 industry policy plan updates. OSFI, Property and Casualty Large Insurance Exposures and Investment Concentration, effective January 1, 2025. OSFI, separate draft banking B-2 guideline, May 21, 2026.