The UK's HM Treasury has designated Google Cloud, Microsoft Azure, and Oracle as "Critical Third Parties" (CTPs) for their role in providing cloud services to financial services.

As revealed on the UK government website on July 10, starting today, July 13, the companies will be subject to direct regulatory oversight aimed at helping protect the UK's financial system.

The move has been motivated by banks, insurers, and financial market infrastructures' increasing reliance on cloud services, meaning that "disruption at a major supplier could affect multiple firms at the same time, potentially impacting services customers depend on."

The designation will mean that the Bank of England, Prudential Regulation Authority, and Financial Conduct Authority will work together to jointly oversee the cloud providers and the services provided to the financial sector. The regulators will have the power to gather information, assess resilience, and work with third parties to address risks to the continuity of critical services, including by making and enforcing CTP-specific rules.

Economic Secretary to the Treasury and City Minister, Rachel Blake MP, said: "We are a world-leading financial center, and maintaining trust in our financial system is essential to its success. These designations will help ensure the critical services financial firms rely on remain resilient, protecting consumers and businesses while supporting growth across the economy."

Nikhil Rathi, chief executive at the FCA, said:  “Critical third parties provide essential services which support innovation and growth. At the same time, when the same providers serve thousands of firms, a single failure can reverberate across the financial system. Operationalizing this regime strengthens our ability to tackle those risks and improve overall resilience, ensuring the UK remains a safe and attractive place to do business."

Rathi added: "The regulators will periodically review whether CTPs continue to meet the designation criteria, making recommendations to HMT, and evaluate the effectiveness of the oversight approach. The Bank, PRA and FCA will continue to work closely with HMT, the financial services industry and designated CTPs as the regime is implemented, while supporting innovation, and UK growth and competitiveness."

All four cloud providers have expressed support for the designation, with Microsoft's deputy chief information security officer for Europe stating that "the designation of Microsoft Ireland Operations Limited as a critical third party marks a new chapter in this relationship, and Microsoft remains fully committed to complying with the relevant oversight requirements and the UK’s cybersecurity and resilience laws."

Michael Jefferson, head of financial services public policy EMEA at AWS, added: "AWS supports the objectives of the UK Authorities to ensure a robust UK financial system. AWS will comply with all applicable regulations, and we remain committed to helping customers to meet their business and operational resilience objectives."

According to a 2024 survey done by the Bank of England and FCA two years ago, Microsoft, Google, and Amazon accounted for 73 percent of cloud computing services to UK financial companies.

With this in mind, the "Big Four" could be the first of many CTPs, with the Treasury noting that it was taking a "targeted and proportionate approach, with these first designations focused on the most critical providers.”

The designation comes after a major AWS outage in October 2025 impacted numerous users and businesses, though mostly in the US.

Among the large UK financial users of cloud computing services is the London Stock Exchange Group. In 2022, Microsoft acquired a stake in the exchange, with the companies stating at the time that LSEG would migrate to Microsoft Azure under a ten-year agreement with $2.8 billion in minimum spend commitments for LSEG.

While having a long-standing contract with Microsoft, LSEG expanded its use of Amazon Web Services (AWS) in April 2025, making AWS its preferred cloud platform for its markets, risk intelligence, and FTSE Russell divisions.