[gruez]

except for short on cme, which requires 100%. http://www.cmegroup.com/education/cme-bitcoin-futures-freque...

[jnordwick]

I think you are reading that wrong. Initial margin is 100% to 110% of maintenance margin (44%) depending on how they classify you (almost everybody here is a speculator not hedger).

Current maintenance margin is about $34k on a single contract (5 BTC).