We are
Fraction.

Jack Lieb is the Founder of Fraction and an NBPA Certified Agent. A former collegiate athlete and coach, Jack understands and cares deeply about his players. 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 worked under NBA legend Jerry Stackhouse and coached NBA player Scotty Pippen Jr while earning a master's degree in applied economics. He was also a Team Captain at Lehigh University, where he graduated with a finance degree and honors distinction. Jack brings a rare combination of on-court knowledge and business acumen; he has structured more than $10 million in compensation for his clients.

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