No — there is currently no reliable public source that confirms John Overdeck is left-handed.

John Overdeck is an American hedge fund manager and philanthropist. He is best known as the co-founder of Two Sigma Investments, a quantitative hedge fund based in New York City.

Before co-founding Two Sigma in 2001, Overdeck worked at D.E. Shaw & Co. and Amazon.com, where he served as Vice President and Technical Advisor to CEO Jeff Bezos.

He holds a Bachelor of Science degree in mathematics from Stanford University and a master's degree in statistics from Stanford. His academic background in quantitative fields heavily influenced his approach to finance.

Through the Overdeck Family Foundation, which he co-founded with his wife Laura, John Overdeck supports initiatives focused on enhancing STEM education and early childhood development. The foundation aims to elevate research, policy, and practice in these areas.