Ill. Admin. Code tit. 11, § 311.35
Superfecta wagering shall not be scheduled on a thoroughbred or standardbred race unless at least six betting interests are carded. In the event of a scratch, superfecta wagering on a thoroughbred or standardbred race in which five betting interests remain is permissible.
(Source: Amended at 39 Ill. Reg. 13714, effective October 5, 2015)