In October 2023, we announced a significant improvement in our wallet infrastructure, introducing newly issued wallet addresses for all users. As a result, the size of all transactions on BitMEX was reduced substantially, improving the use of block space for all users of Bitcoin.
The impact? We now offer BitMEX users significantly lower Bitcoin network fees for withdrawals.
This was made possible as all BitMEX addresses used for deposits and withdrawals are now MPC single-signature native segwit addresses (also known as Bech32 or “bc1” prefix addresses).
BitMEX has always passed 100% of the withdrawal fee directly to miners as the on-chain transaction fee – and continues to do so. The minimum network fee when withdrawing Bitcoin is therefore set dynamically based on the prevailing mempool fee rates, and can be viewed on the withdrawal page.
Our historic multi-signature wallets imposed a worst-case spend of 618 vB (at a single input) while our new wallets reduce this to 222 vB. This means we are bidding for less block space, and consequently, the cost to our users is lowered by 50-65% (compared to the previous cost of withdrawals for equal fee rates).
We still require a minimum fee on transactions as spikes in the mempool are often sudden and unpredictable. However, we are halving our minimum fee from 0.0002 BTC to 0.0001 BTC, which will make it among the lowest in the industry.
What are the Impacts to the Bitcoin Network?
As part of our commitment to the health of the Bitcoin ecosystem, we have removed over 400,000 legacy multi-signature UTXOs from the unspent transaction set carried by every full Bitcoin node. This can be seen in our Proof of Reserves and Liabilities dataset size reduction here.
The move demonstrates our commitment to an efficient Bitcoin network and affordable fees whilst maintaining wallet security and full transparency.
What Do Users Need to Do?
This is a reminder to users who still need to update their external systems to the refreshed deposit addresses. Please ensure all Bitcoin deposits are made to the current addresses to avoid delays or administrative charges for the receipt of funds, as we remove old addresses (starting with 3BMEX or bc1qmex) from our real-time systems.
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In the meantime, if you have any questions, please contact Support who are available 24/7.