Anthropic has expanded its Glasswing partner programme fourfold, inducting 150 new organisations including the first non-US members, while UK banks have notably been excluded from the initiative. In parallel, OpenAI is offering UK financial institutions access to GPT-5.5, highlighting a competitive dynamic in AI partnerships within the regulated financial sector. The exclusion raises questions around data sovereignty, regulatory compliance, and which AI vendors UK-regulated entities can practically partner with.

Architect’s Take: Cloud security architects at UK financial institutions should assess the compliance and data residency implications of both OpenAI and Anthropic offerings before committing to either platform, paying close attention to FCA and PRA guidance on third-party AI risk and ensuring any AI partnership agreements include robust contractual controls around data handling and model governance.

Original advisory: UK banks offered access to OpenAI’s GPT-5.5 amid exclusion from Anthropic’s Glasswing expansion

Anthropic has expanded its Glasswing partner programme fourfold, inducting 150 new organisations including the first non-US members, while UK banks have notably been excluded. OpenAI has moved to fill the gap by offering UK financial institutions access to GPT-5.5. The development highlights growing competitive dynamics in enterprise AI access and raises questions about supply chain concentration risk for financial sector security teams.

Architect’s Take: Cloud security architects in UK financial services should assess the security posture, data residency commitments, and compliance certifications of any AI provider they are offered as an alternative — do not treat OpenAI’s GPT-5.5 access as a like-for-like replacement for Anthropic without conducting due diligence on API security controls, data handling agreements, and regulatory alignment with FCA/PRA expectations.

Original advisory: UK banks offered access to OpenAI’s GPT-5.5 amid exclusion from Anthropic’s Glasswing expansion