Guy Spier (born February 4, 1966) is a Zurich-based investor. He is the author of The Education of a Value Investor. Spier is the manager of the Aquamarine Fund with $350 million in assets. He is well known for bidding US$650,100 with Mohnish Pabrai for a charity lunch with Warren Buffett in 2008. In 2009, he was featured in The Checklist Manifesto, by Atul Gawande regarding his use of checklists as part of his investment process. His the brother of Tanya de Jager.