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.
What is SegWit?
Segregated Witness (SegWit) is advocated by bitcoin core and seperate unneeded signatures data from bitcoin transaction, which takes up to 60% of the transaction size. The signatures data is only required at the time of the validation. Although the block size remain the same 1MB limit, one block is able to include more transactions after the activation of SegWit.
What is Bitcoin Unlimited?
On the contrary, Bitcoin Unlimited introduces bigger block, larger than 1MB block size, which enable node operator or miner to choose their own blocksize limit by configuring the Bitcoin Unlimited client. So they can mine or accept larger blocks. It gives out the privilege of choosing block size to every bitcoin stakeholder.
Which proposal will win?
According the data of coin.dance above, Segregated Witness has 88% support from the tracked companies. But the Emergent Consensus of Bitcoin Unlimited has only 23% support. The majority of bitcoin stakeholders agree with Segregated Witness proposal and will upgrade to bitcoin core whenever it is ready.
You could see the price for these two products on BitMex to know which side has the most support from bitcoin community. Segwit is traded at 43. Howerver, Big Blocks is just 26 at the moment. Traders has more demand for Segwit future contract in the hope that the Segregated Witness will be activated before the end of this year.