Ostium is an onchain perpetuals exchange built on Arbitrum that lets anyone long or short real-world assets - stocks, commodities, indices, forex and crypto - directly from a self-custodial wallet, with up to 200x leverage and no broker in the middle. Founded by Harvard classmates and former Bridgewater hands Kaledora Kiernan-Linn and Marco Antonio Ribeiro, Ostium uses synthetic perpetuals and a custom oracle system to bring traditional markets onchain. It has processed tens of billions in cumulative trading volume and raised $27.8M total, including a $20M Series A co-led by General Catalyst and Jump Crypto in December 2025.
Kaledora Kiernan-Linn is the co-founder and CEO of Ostium, an onchain exchange for trading perpetual futures on real-world assets like oil, metals, equity indices and FX. A former professional ballet dancer who performed at the Royal Danish Ballet before studying neuroscience at Harvard, she met her cofounder running arbitrage strategies out of a Cambridge hacker house and built Ostium into the category leader for 'perpetual-ified' traditional assets. In December 2025 the company raised a $20M Series A led by General Catalyst and Jump Crypto at a roughly $250M valuation, and she was named to the Forbes 30 Under 30 list in Finance the same year.