Cross-domain enterprise-risk and climate-risk papers, written to be checked — every figure traced to a named primary instrument.
On 13 July 2026 HM Treasury designated four cloud providers as Critical Third Parties to the UK financial system — the first use of the designation power in the Financial Services and Markets Act 2023. For insurers this is not an IT story. It is an operational-risk, capital and board-reporting story, and it makes a concentration firms have long tolerated newly legible to their supervisors.
Impact tolerances are set against causes when they should be set against effects. A short argument for reframing operational resilience around what the customer loses rather than what the firm's system does.
A transmission channel is the route by which a shock in one domain becomes loss, capital pressure or constraint in another. Every channel has a direction, a latency and an amplification factor — none of which a correlation coefficient can express. The paper sets out why correlation matrices keep failing in the tail, and what changes when channels are modelled as objects rather than absorbed into a coefficient.
What the December 2025 supervisory statement expects of insurers, where it goes beyond SS3/19, and which expectations land in the ORSA rather than the disclosure.
Where a severe physical pathway stops being an underwriting question and becomes an operational one — and why the two are modelled apart when they arrive together.
The first in the series. Cascade models fail not because the mathematics is wrong but because the perimeter is drawn before the cascade is understood.