UK finance rehearses a global cloud outage: SIMEX26 with 38 firms
Serguey Asael Shinder2 min readThe Cross-Market Operational Resilience Group (CMORG) completed its biennial sector-wide simulation, SIMEX26, on 8 October, the Bank of England said the next day. This year's scenario was a global disruption to cloud-based services.
Who took part. CMORG is chaired by the Bank of England and UK Finance, with HM Treasury, the Financial Conduct Authority and the wider sector. The exercise involved the 38 largest and most systemically important banks and market infrastructure operators, was opened by the Economic Secretary to the Treasury and hosted by the London Stock Exchange Group. It included a live meeting of the Bank-chaired Cross Market Business Continuity Group, which steers the sector's collective response to systemic incidents through the Sector Response Framework.
What it was — and was not. The Bank says the scenario was not informed by any specific threat intelligence; it was built with industry experts. Earlier rounds in 2022 and 2024 covered a cyber-attack on a major bank and disruption to critical infrastructure outside finance. Choosing a cloud outage this time reflects how much of the sector now runs on a small number of shared providers — the concentration risk that the UK's critical third parties regime is designed to address.
What happens next. The Bank "now expects firms to take action based on the exercise" to strengthen their resilience and their response to severe operational and cyber scenarios. Deputy Governor Katharine Braddick, who heads the PRA, called it "an important demonstration of the UK financial sector's commitment to operational resilience". The Bank lists recent CMORG work on third-party resilience, secure adoption of AI and cyber recovery for the most severe scenarios.
Why it matters for sterling markets. Payment systems, clearing houses and the gilt market's settlement plumbing all sit inside this exercise. A cloud outage that halts settlement or margin calls for hours is a market-functioning event, not just an IT one — which is why the authorities rehearse it with the market infrastructures in the room. The findings themselves are not published; the visible output will be in supervisory expectations over the coming months.
Source: Bank of England, "CMORG holds sector-wide cloud outage simulation exercise", 9 October 2026 — https://www.bankofengland.co.uk/news/2026/october/cmorg-holds-sector-wide-cloud-outage-simulation-exercise