BitMex offer two new prediction futures for segwit ( B_SEGWITZ17 ) and emergent consensus or big blocks ( B_BLOCKSZ17 ). Segwit(Segregated Witness) future allows users to bet on the possibility of the activation of the Segwit proposal BIP141 before Dec 31, 2017 at 12:00 UTC. Big Block (Bitcoin Unlimited) is to bet on whether or not larger than 1MB block size will be mined on the majority chain, and that chain remains the majority chain for 75% of the next 2016 blocks before Dec 31, 2017 at 12:00 UTC.
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