Diameter Pay has raised $10 million in a Series A round co-led by CMT Digital and Lightspeed Faction, with participation from SixThirty Ventures, the Stellar Development Foundation, Tech Council Ventures, Onigiri Capital and Bitrock Capital. The equity financing began in April and closed in July and is the company’s first external funding since its 2023 founding, after a period of self-funding under Founder and CEO David Lighton. Diameter Pay provides U.S. dollar payments infrastructure to banks, fintech firms and digital-asset exchanges, enabling overseas fintechs to offer virtual U.S. dollar accounts while payments and compliance run through U.S. sponsor banks including Fortage Bank and SSB Bank. The company said it has processed more than $10 billion in payments so far this year, serves banks and large fintech clients in hubs such as Switzerland and Singapore, and has more than 10,000 end users. Proceeds will expand banking and payments infrastructure, strengthen cross-border dollar payment technology and compliance, and enhance stablecoin and foreign-exchange capabilities. CMT Digital will take a board seat, Lightspeed Faction and SixThirty Ventures will serve as board observers, and former Fidelity Investments President Robert Pozen has joined as senior adviser to the board.