Thomas Gieselmann

Thomas Gieselmann is a Founding Partner at Headline, a global venture capital firm, and is based in San Francisco, California. He co-founded the firm, originally known as e.ventures, in 1997 alongside Mathias Schilling after the two met while managing operations for AOL in Germany. With early financial backing from Bertelsmann, Gieselmann helped build the firm's proprietary deal-sourcing database in the early 2000s and recently supported Headline's $865 million fundraise in September 2024. His investment portfolio features prominent technology companies, including NGINX, which was acquired by F5 Networks, Segment, which was purchased by Twilio, Data.ai, which was acquired by Sensor Tower, and the publicly traded SEMrush. Drawing on his early entrepreneurial background in publishing, Gieselmann currently focuses on United States investments, targeting disruptive software sectors like developer tools, open-source infrastructure, artificial intelligence, and financial technology.