Entrepreneur, Builder. General Partner, South Park Commons.Jimini Health co-founder, President

Mark has built and run companies at the forefront of new technologies for thirty years. In 1994, he founded Small World Sports, the world’s first online fantasy sports business, which he later sold to Paul Allen’s The Sporting News. In 1995, he spun out one of the world’s first web agencies, Small World Software, which he sold to iXL before its 1998 IPO. In 2003, Trip Hawkins convinced Mark to move to the Bay Area to co-found Sequoia and Kleiner Perkins-backed mobile games pioneer Digital Chocolate. Mark was then recruited to join loopt as the “adult supervision” for Sam Altman (Sam didn’t need any supervision). Later, Vinod Khosla recruited Mark to run mobile VOIP pioneer iSkoot, which he sold to Qualcomm in 2010. Mark spent four years as the Chief User Engagement Officer at Guardant Health, which raised more than $500M before its 2019 IPO, and was the CBO for Immunai, a world-leading AI-driven biotech operating at the intersection of machine learning and genomics that raised more than $300M during Mark’s tenure. In 2023, Mark co-founded Jimini Health, which is leveraging LLMs and cutting-edge science to develop radically more effective, engaging, and scalable mental health solutions. In 2023, Mark co-founded Near Horizon to pioneer a new approach to venture building. Near Horizon partners with entrepreneurs at company formation to build AI-powered companies, providing both capital and hands-on help. Mark has advised or invested in numerous startups, including Gerson Lehrman Group, Gusto, Elation EMR, Akash Network, SafeGraph, and Luminopia. Mark earned his BA from Harvard, where he concentrated in Computer Science. He lives on the Stanford campus with his wife and two (adorable) daughters.