Bitcoin Unlimited – BitMEX Blog The official blog of BitMEX, the Bitcoin Mercantile Exchange. Mon, 26 Feb 2018 08:12:28 +0000 en-US hourly 1 Bitcoin Unlimited – BitMEX Blog 32 32 78374597 On Potential Post-Fork Contract Settlement Sat, 18 Mar 2017 16:12:52 +0000 Traders,

Recently, we published A Statement on the Possible Bitcoin Unlimited Hard Fork, a statement of our views on the potential fork to Bitcoin Unlimited, its consequences, and further requirements we consider necessary for adoption.

Many have asked us about the settlement of our existing Bitcoin futures: the Bitcoin/USD series (XBT), the Bitcoin/CNY series (XBC), and the Bitcoin/JPY series (XBJ).

In the event of a fork in which both chains remain viable into the future and maintain double-digit percentages of the original Bitcoin hash rate (a “Contentious Fork“), we will take the following actions:


  • As we predict the value of Bitcoin to then be split between BTC and BTU, currently-listed futures at the time of the fork will settle on the sum of BTC and BTU.
    • It may not be possible to predict or plan to get reliable pricing data from our current Index exchanges, or they may not list the minor coin at all. In the event of a Contentious Fork BitMEX reserves the right to move all Bitcoin derivatives to Last Price Protected Marking, until a stable index can be composed.
    • We will compose two indices representing the majority and minority chain, and the sum will be taken to compose the Mark and Settlement Prices. The indices will be separated in case not all component exchanges list the minority chain.
  • Contracts listed after the fork will settle on the BTC or the BTU price, but not both. Only contracts listed pre-fork will settle on the sum.
  • Perpetual swap contracts will be timed to switch underlying indices in tandem with a futures contract. Ample notice will be given. Like futures, the new index will reference only one chain.


  • During the time immediately after the fork, BitMEX reserves the right to suspend withdrawals to avoid replay attacks and double-spending and account for the development effort required to accommodate a hard fork.
  • Users will be able to withdraw the minor currency, but not deposit it. We have no plans to support multiple margin currencies. Balances of the minor currency will be calculated via a snapshot at the time of the fork and maintained separately to major currency’s margin balance, as further mixing of the currencies thereafter could lead to improper attribution.
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