Flex Raises $15 Million in Series A to Re-Engineer the Future of Health Spending

Flex, a stripe for HSA/FSA payments, led by Sam O'Keefe and Miguel Toledo, has raised $15 million in Series A, co-led by First Round Capital and CoreVC, with participation from Rethink Capital and Cameron Ventures.

Americans hold nearly $150 billion in HSAs and FSAs, yet billions go unspent each year due to confusion over eligible expenses and limited retailer acceptance. Consumers face the hassle of paying out of pocket and filing for reimbursement, while the average account holder forfeits around $450 annually in unused funds. Retailers miss out too, often unable to accept HSA/FSA payments even for qualified medical products.

Flex’s mission is to improve health by making consumer-directed spending simple, seamless, and ubiquitous. The company partners with retailers to enable HSA/FSA payments at checkout and boost awareness through merchandising and marketing—driving over 50% higher average order value, up to 30% checkout conversion lifts, and a 20% increase in free-to-paid plan conversions.

Flex simplifies HSA/FSA payments for consumers and merchants—making purchases compliant, seamless, and scalable. With flexible integrations, eligibility management, and performance insights, Flex unlocks health-focused spending as retail’s next growth channel in a $500B wellness market.