15 U.S. Code § 6307b - Protection from coercive contracts
(a) General rule
(A) A contract provision shall be considered to be in restraint of trade, contrary to public policy, and unenforceable against any boxer to the extent that it—
(i) is a coercive provision described in subparagraph (B) and is for a period greater than 12 months; or
(B) A coercive provision described in this subparagraph is a contract provision that grants any rights between a boxer and a promoter, or between promoters with respect to a boxer, if the boxer is required to grant such rights, or a boxer’s promoter is required to grant such rights with respect to a boxer to another promoter, as a condition precedent to the boxer’s participation in a professional boxing match against another boxer who is under contract to the promoter.
(3) No subsequent contract provision extending any rights or compensation covered in paragraph (1) shall be enforceable against a boxer if the effective date of the contract containing such provision is earlier than 3 months before the expiration of the relevant time period set forth in paragraph (1).
(b) Promotional rights under mandatory bout contracts
No boxing service provider may require a boxer to grant any future promotional rights as a requirement of competing in a professional boxing match that is a mandatory bout under the rules of a sanctioning organization.
(c) Protection from coercive contracts with broadcasters
Subsection (a) of this section applies to any contract between a commercial broadcaster and a boxer, or granting any rights with respect to that boxer, involving a broadcast in or affecting interstate commerce, regardless of the broadcast medium. For the purpose of this subsection, any reference in subsection (a)(1)(B) of this section to “promoter” shall be considered a reference to “commercial broadcaster”.