We are
Fraction.

Jack Lieb is the Founder of Fraction and resides in Chicago, Illinois. A licensed NBPA certified agent and NIL agent, Jack guides players towards success. He built Fraction on the belief that athletes deserve precise, trusted representation — not just at the negotiating table, but throughout all areas of their life.

Jack has experience as a Graduate Assistant at Vanderbilt University, where he coached multiple NBA players while earning a master's degree in applied economics. He would go on to start Ex-Pats in the TBT Tournament, and has also coached for Maccabi and the Illinois Wolves. He was also a Team Captain for the Men's Basketball Team at Lehigh University, where he graduated with a finance degree and honors distinction. Jack brings a rare combination of on-court experience and business acumen; he has structured more than $15 million in compensation for his clients and has helped more than 100 athletes play in college.

Recognized as one of the 2025 Top 80 Most Influential People in NIL by Silver Waves Media, Jack continues to shape the future of athlete representation through Fraction's NIL, NBA, player development, FIBA, marketing, and analytics services.