Flex, an AI-native private banking platform for mid-market business owners, just closed a $70 million Series B1. The round was led by Halo Fund — the investment firm set up by Qualtrics founder and Utah Jazz owner Ryan Smith — with participation from Portage Ventures, Wellington, Crosslink Capital, 53 Stations, Titanium Ventures, Spice, and Florida Funders.
The company says its annualised payment volume has crossed $10 billion, growing roughly fourfold year on year. Revenue is up threefold since December. Headcount stands at 110 and is expected to pass 200 by the end of 2026. The round brings Flex’s total equity raised to $180 million, alongside $300 million of debt.
Investors are clearly interested. But what does Flex actually do that is different from every other fintech?
The Problem Flex Solves
Flex targets what it calls the “middle market”: business owners with revenues in the tens to low hundreds of millions. These people occupy an awkward position in finance. They are at once the company’s finance department and its wealthiest individual customer. Their vendors are scattered across different countries. They stack up two or three providers — and the fees that come with them — simply to pay someone abroad.
Flex puts the US addressable market at roughly 350,000 such owners, responsible for about 40% of private-sector payroll. The global figure is around 3 million. These owners are multi-entity, multi-currency, and multi-jurisdiction whether they planned to be or not.
Traditional private banks are built for inherited wealth, not operating businesses. Consumer fintech apps are built for individuals, not companies. Flex sits in the middle, bundling credit, banking, payment processing, bill pay, expense management, and treasury into what it calls an “agentic back office” — software that moves money without requiring a human at every step.
What Flex Global Actually Does
The product that launched alongside the funding round extends the platform internationally. Flex Global promises stablecoin payment rails in more than 100 countries, multi-currency accounts across 76 countries covering 32 currencies, and private credit in more than 20 countries.
Cross-border payments settle in minutes rather than days. The stablecoin layer is designed to stay invisible: an owner paying a supplier in Warsaw pays them the same way they would pay one in Dallas, and never touches a crypto wallet or sees a blockchain address. That invisibility is the entire point — you should not have to understand stablecoins to benefit from them.
That bet depends on infrastructure that only recently became usable at scale. Visa’s settlement pilot reached a $7 billion annualised run rate in April. Genuine stablecoin payment volume — excluding bots and arbitrage — roughly doubled in 2025 to about $390 billion, most of it business-to-business, according to research by Artemis and McKinsey.
Incumbents noticed. Mastercard’s $1.8 billion purchase of BVNK was the clearest signal yet that stablecoin payments had graduated from pilot to plumbing.
The Bigger Picture
Flex is part of a wave of agentic banking platforms built to let software, not people, move money. Founder Zaid Rahman puts it simply: “Middle-market business owners are one of the most important and underserved customers in finance globally.”
Halo Fund’s Ryan Smith framed the gap differently: “Their business and personal financial lives are completely intertwined, but every bank treats them as two different customers.” What Halo brings beyond the cheque is distribution — its remit runs across the NBA, the NHL, and Formula 1, an odd sales channel for a bank until you remember that Flex’s customers were never in Silicon Valley’s address book to begin with.
Flex’s biggest customer categories by logo count are construction, wholesale, and multinational businesses. Next on the roadmap: personal credit, rewards cards, treasury, travel, and mortgages. Whether the owner of a mid-sized construction firm wants their bank to book their flights is a question Flex’s next round will presumably answer.