Flex Raises $60 Million Series B to Build AI “Private Bank”

Flex has raised a $60 million Series B round to build what it calls an AI-native private bank for high net worth business owners.

The San Francisco startup said Thursday the equity financing was led by Portage, with backers including CrossLink Capital, Spice Expedition, Titanium Ventures, Wellington, Companyon Ventures, Florida Funders, FirstLook Partners and Tusk Venture Partners. The round brings Flex’s total equity funding to $105 million.

The deal follows a burst of activity this year. Earlier in 2025, Flex secured $200 million in debt and $25 million in equity, then proceeded to quadruple revenue and triple annualized payments volume to $3 billion as more owners adopted its all-in-one platform.

Flex, founded by Zaid Rahman, focuses on an often overlooked slice of the economy: high net worth middle-market business owners generating roughly $3 million to $100 million in revenue and employing about 40% of U.S. payroll. These founders typically manage both company finances and significant personal assets across a jumble of banking, payments, credit and investment tools.

Flex wants to collapse that sprawl into a single system.

The company’s suite spans business credit cards, working-capital lines, banking, payments, expense management and personal finance tools. Its business card, which offers 60-day float on every transaction, often serves as the entry point before customers layer on banking and software products.

The new funding lands as Flex rolls out Flex Elite, an invite-only consumer card and membership aimed squarely at Amex’s Centurion-tier customers. Flex Elite extends the platform into owners’ personal lives, supporting the company’s push to be a unified “private bank” that tracks every dollar from business income to personal spending.

To power that vision, Flex is leaning into AI agents that sit across credit underwriting, expense review, cash management, payments and a middle-market ERP stack. The idea is to turn the platform into an always-on finance team and “AI CFO,” cutting operating costs for Flex while giving owners real-time, plain-language insight into their money. Executives say the technology also helps Flex move faster than traditional banks on product updates, compliance checks and customer support.

Backing that software layer is a private credit arm that uses agentic underwriting to price risk and keep more lending economics in-house. As customers run more of their financial lives through Flex, executives say, the data flywheel tightens and the model becomes harder for rivals to copy. Flex plans to use the capital to expand hiring and product.