Hadi
Solh

Somewhere inside Goldman Sachs' Middle East investment banking team, a young analyst was doing the math that most bankers never do: what happens to the companies behind the deals? Not the Fortune 500s. Not the institutional players. The construction firm in Houston waiting 110 days to collect on a completed job. The mid-market supplier financing payroll out of its own pocket while the invoice sits in someone's accounts payable queue.

That analyst was Hadi Solh. And rather than just noticing the gap, he eventually decided to build something for it.

Solh grew up watching the construction industry from the inside - a family with roots in building and the particular financial anxiety that comes with it. Every project is a float. Every invoice is a bet. The work gets done in April; the money might arrive in August. Traditional banks look at these companies and see complexity. Solh looked at them and saw an addressable market that nobody had bothered to address properly.

In 2021, after stints at Credit Suisse First Boston, Goldman Sachs, and McKinsey - plus an MBA from MIT and an MPA from Harvard - Solh co-founded Flexbase alongside Zaid Rahman. Their first product was audacious in its simplicity: a business credit card offering 60 days of interest-free financing, designed specifically for the construction industry. It was the construction industry's first such card. TechCrunch called it a game-changer for an industry where collection cycles routinely stretched past 100 days. Flexbase called it the beginning.

The pivot that followed wasn't a pivot - it was an expansion. The construction-specific card revealed a much larger thesis: that the entire class of mid-market business owners, those generating $3M to $100M in annual revenue, was being systematically underserved by every financial institution in America. Not because these owners weren't creditworthy. But because traditional banks had built their infrastructure for two customer types: large enterprises with armies of finance staff, and consumers with simple individual needs. The business owner who is both - running a company, managing personal wealth, paying international suppliers, handling employee expenses - had nowhere to go.

Flex became that somewhere.

From Card to Super App: The $490M Build

Series after series, Flex kept compounding. A $2.5M pre-seed. A $20M equity round paired with $100M in debt. Then a $25M equity raise with a $200M facility from Victory Park Capital. Then - in December 2025 - a $60M Series B led by Portage, with Wellington, Crosslink Capital, Titanium Ventures, and others joining in. Total equity raised: $105M. Total funding including debt facilities: over $490M.

Those numbers tell a story about how fintech infrastructure gets built. Equity buys the product and the team. Debt buys the lending book. Solh and Rahman structured Flex's capital stack to do both - a move that reflects Solh's 20+ years of corporate finance muscle memory. You don't learn to structure a $200M debt facility at a startup. You learn it at Goldman and Credit Suisse.

The platform Flex operates today is genuinely broad. Business credit cards with net-60 terms and up to 1.75% cashback. Business banking with up to 2.47% APY on savings - a rate that embarrasses most traditional business checking accounts. Global payments to 180+ countries. AP/AR automation that integrates with accounting software. And at the center of it all, something Flex calls "Owner Intelligence" - an AI layer that functions as a virtual CFO, analyzing cash flow, flagging anomalies, automating payment workflows, and surfacing decisions that owners would otherwise need a finance team to see.

The result: $3B in annualized payment volume - triple what it was 12 months earlier. Revenue quadrupled year-over-year to $150M. Fast Company put Flex on its 2026 Most Innovative Companies list. The target market, Flex says, is the segment of business owners who power roughly 40% of US payroll. That's not a niche. That's the spine of the economy.

The Other Life: Deep Tech VC and Quantum Boards

While running a Series B fintech out of San Francisco, Hadi Solh maintains a parallel existence as a venture capitalist. He is Managing Partner at Atmos Ventures, a firm focused on seed and Series A investments in European deep technology companies. It is, by any metric, an unusual combination: active operating founder and active GP, simultaneously.

The board seats he holds make the point sharply. Solh joined the board of Oxford Ionics in 2021 - a quantum computing company spun out of Oxford University, working on trapped-ion quantum processors. He is also a board director at Nethone, a cybersecurity company specializing in AI-driven fraud prevention. Neither of these is adjacent to consumer payments. They sit at the frontier of what computing and security will look like in a decade.

This is where the MIT-Harvard combination starts to make more sense. The MBA gave Solh the corporate finance framework. The MPA - a Master of Public Administration from Harvard, focused on policy, economics, and development - gave him something harder to quantify: an understanding of how institutions work, where they fail, and what it takes to build infrastructure that scales across systems. The combination is unusual in the startup world. Most founders go deep on one discipline. Solh went deep on several and then built an operating system to connect them.

Based in Dubai while co-founding a San Francisco fintech company and running a European deep tech fund, Solh operates across three continents from a single base. It is either a testament to modern remote infrastructure or an extraordinary tolerance for time zones. Probably both.

The Technology Bet

Flex's technology stack is a tell. The company runs on Salesforce CRM and Salesforce Analytics. Looker and Tableau for data. TypeScript and PostgreSQL for core infrastructure. Google Cloud Platform. Plaid and Experian for financial data. Multiple fraud prevention layers: Kount, Sift, Sardine, ThreatMetrix, MaxMind, Iovation, NICE Actimize. LexisNexis Risk Solutions. Visa. Figma for design. Lever for recruiting. GitHub for engineering. ChatGPT and Gemini in the AI stack.

The fraud stack alone - running seven separate systems simultaneously - tells you something about the risk profile of the customer Flex serves. These are real businesses with real payroll and real supplier relationships. Getting a payment wrong isn't an inconvenience; it's a crisis. Solh's finance background meant Flex built its risk infrastructure like a bank, not like a startup.

The AI layer - Owner Intelligence - is where Flex is placing its biggest bet on differentiation. Rather than offering AI as a feature, Flex has repositioned it as the core product: an AI CFO that every business owner gains access to when they join the platform. In an economy where small businesses can't afford to hire a CFO and large ones already have armies of them, the middle market has historically had to guess. Flex is betting that AI changes that math.