[destructaball]

30% is far too small of an initial margin for such a volatile commodity.

The initial margin is expected to cover a the movement of an observable through making the margin call, the period of time the margin call could be filled, declaring the counter-party in default and closing out the position. This normally adds up to a minimum of 2 working days.

Saying that it's beyond the realms of possibility for bitcoin to jump or fall 30% in 2 days seems ridiculous.

[tome]

The highest daily volatility ever was 15% and it's currently around 4%, according to https://bitvol.info/ . Two times the highest daily standard deviation ever doesn't seem so unreasonable.

[1053r]

That's the highest AVERAGE ROLLING 30 DAY volatility.

For example, on Dec 7, 2013, volatility between the high and the low was 54.6%. [1] However, it was lower for the other days of all 30 day periods that include that day, and averaged out to under 15%.

1 - https://www.coindesk.com/price/

[baddox]

Do you have any data on what the largest 48-hour jumps in Bitcoin price have been?

[pmontra]

This could be the largest one in absolute value: according to http://www.xe.com/en/currencycharts/?from=XBT&to=USD&view=1W it went from 11258 USD on November 28 to 9136 on November 29. Then it went up and down again to 9217 on the night of November 30.