For now Bitcoin is down 18% from its record high - closing in on a bear market...

In any case, based on the CME's preliminary term sheet, bitcoin trading limits would kick in when the price of its bitcoin futures move 7%, 13% or 20% up or down from the previous day’s closing price. The first two thresholds, for 7% and 13% moves, are “soft” limits, which would trigger a two-minute pause in trading of bitcoin futures. The 20% limit would be a “hard” stop on how far CME’s bitcoin futures could swing on any day.
By comparison, the CME has similar staggered volatility control on its popular E-mini S&P 500 futures contract, which also has three successive price-fluctuation limits at 7%, 13% and 20% during regular trading hours. A nighttime limit of 5% was hit in the S&P 500 futures on Nov. 8, 2016, when news of Donald Trump’s upset win in the U.S. presidential election triggered wild volatility in stock-market futures, only for the S&P to surge 21% in the 12 months since.

Of course, bitcoin will be a far "wilder" and more volatile instrument than the S&P 500 (one hopes). According to Coindesk calculations, so far in 2017 there have been two days in which bitcoin’s price swung more than 20% in a single day. There were 11 days in which it moved at least 13%, and 69 in which it moved at least 7%.

http://www.zerohedge.com/news/2017-11-10/where-cme-would-halt-bitcoin-plunge