Muhammad Ali Expansion Act This bill amends the Professional Boxing Safety Act of 1996 to: (1) establish definitions for "fighter," "combat sport competition," and "mixed martial arts"; and (2) include individuals who fight in a professional mixed martial arts competition or other professional combat sport competition, such competitions, and the professional combat sports industry within the scope of such Act. The bill requires the Association of Boxing Commissions, within two years after enactment of this bill, to establish: (1) guidelines for minimum contractual provisions that should be included in bout agreements and mixed martial arts and other combat sport contracts, and (2) guidelines for objective and consistent written criteria for the ratings of mixed martial arts and other combat sports. The bill applies conflict of interest provisions that prohibit a promoter from having a financial interest in the management of a boxer, or a manager from having a financial interest in the promotion of a boxer, to fighters participating in a mixed martial arts or other combat sport competition scheduled for 11 minutes or more.