The U.S. Commodity Futures Trading Commission (CFTC) on Friday proposed a rule that would ban listed derivatives used to bet on U.S. elections and other major real world events.

Regulators advanced a plan to ban derivatives contracts based on political elections, athletic competitions and awards contests, in a bid to clarify the boundaries between gambling and financial markets.

A top financial regulator took a major step toward directly banning derivatives from being used to bet on political contests and sports games — throwing up another hurdle for those hoping to wager on November’s US election.