Flagstone appoints Arman Tahmassebi as new CEO amid record £19bn growth
Flagstone, the UK’s largest savings platform, has named Arman Tahmassebi as its new chief executive. He takes over from Simon Merchant, who is leaving the role for health reasons but will remain as chairman. The company now manages nearly £19 billion in savings for individuals and businesses.
Tahmassebi joined Flagstone as chief operating officer in May 2024. Before this, he spent over 25 years in fintech, holding senior roles at LendInvest, ETX Capital and IG. His experience includes leading operations and shaping long-term business strategies.
During his time as COO, Tahmassebi helped drive the company’s growth. In 2025, Flagstone’s business savings division saw deposits from UK SMEs rise by 82%, reaching £3.1 billion. By the end of the year, total savings under administration had grown by 21%, hitting almost £19 billion. Simon Merchant, the outgoing CEO, will continue supporting the company as a strategic adviser. His departure follows health-related reasons, though he remains involved in a non-executive capacity.
Tahmassebi’s appointment comes as Flagstone reports strong financial growth. The platform now oversees nearly £19 billion in assets, with a significant rise in SME deposits. His leadership will guide the company’s next phase of expansion.
