Peterffy's letter to the CME is short and fun reading. https://www.interactivebrokers.com/download/11-IB17-1145-tp-letter-to-futures-trading-commission.pdf htt

Peterffy's letter to the CME is short and fun reading. https://www.interactivebrokers.com/download/11-IB17-1145-tp-letter-to-futures-trading-commission.pdf https://www.interactivebrokers.com/download/11-IB17-1145-tp-... [PDF] His doomsday scenario is based on the Bitcoin price rising rapidly. The CME's volatility limits would kick in, preventing shorts buying to cover their positions. This leads to "ruin" for them and the CME, and contagion for the real economy. He has a good point, since losses on short positions are theoretically infinite, there's no way to put up enough margin for perfect safety.