> If you collected 25 percent margin from someone who was short bitcoin on Monday, they would have blown through it by this morning Futures are settled daily,

> If you collected 25 percent margin from someone who was short bitcoin on Monday, they would have blown through it by this morning Futures are settled daily, so the risk is only of a 25% move in one day. I agree it's a risk, but much less of a risk than if the futures were settled every 4 days as you were suggesting :)