What is Bitcoin Segwit2x?

Bitcoin Segwit2x is a proposed change which is intended to improve the speed and cost of Bitcoin transactions. If the upgrade is not universally accepted, it may create two Bitcoin blockchains via a fork of the Bitcoin network.
To learn more about forks, check out our blog post.
Are my funds currently on Coinbase safe?
Yes. Any funds on Coinbase before, during, and after the fork will be continue to be stored securely.
When exactly will the fork happen?
The Bitcoin Segwit2x fork will take place when block #494,784 is mined. This is projected to happen on November 16.
Will a new asset be created following the fork?
Yes. The result of the fork will be two different blockchains, which means there will be two distinct digital assets.
What will Coinbase call these two blockchains?
Following the fork, we will continue referring to the current bitcoin blockchain as Bitcoin with the symbol ‘BTC’. We will refer to the new blockchain resulting from the fork as Bitcoin2x with the symbol ‘B2X’.
If the Segwit2x change is accepted by most users, we may choose to rename these blockchains at a later date.
Edit: At the time of the fork, the existing chain will be called Bitcoin and the Segwit2x for will be called Bitcoin2x. Ultimately, we will call the fork with the most accumulated difficulty Bitcoin. We will wait for a period of time after the fork, before finalizing the naming.
What is accumulated difficulty?
Each block on the bitcoin blockchain is mined with a difficulty setting, which roughly indicates how much work needs to be done to mine a block. Accumulated difficulty will be measured as the sum of the difficulty of each block mined since the fork.
What action do I need to take? Do I need to withdraw my funds from Coinbase to have access to B2X?
No action is required on your part. All Coinbase users with a BTC balance at the time of the fork will automatically be credited with an equal balance of B2X.
What if my buy order was in progress during the fork?
You will only receive B2X for the amount of bitcoin present in your account at the time of the fork. Pending BTC purchases at the time of the fork will not be granted any B2X.
For example, if you buy 1 BTC on November 16 with a bank account, this purchase will likely be pending for 5 business days as we wait for your funds to be transferred from your bank. In this circumstance, you would receive your 1 BTC after the fork, but would not also be granted 1 B2X.
Will Coinbase be operating as normal during the fork?
We will disable buys, sells, sends, and receives for bitcoin approximately 8 hours before the fork. We will re-enable bitcoin services as soon as possible afterward.
Will I be able to buy/sell/send/receive both types of Bitcoin on Coinbase?
Coinbase will support buys, sells, sends, and receives for both BTC and B2X. Services for both chains may be disabled several hours before and 24–48 hours after the fork. We’ve posted a general timeline here, and plan on sharing more specific details as we get closer to the fork.
Is there replay protection built in to Bitcoin Segwit2x? Do I need to take any precautions before sending B2X from Coinbase?
Because Bitcoin and Bitcoin Segwit2x will have identical blockchains up until the point of the fork, it is possible to send the same transaction on one chain and then “replay” it on the other. This can lead to inadvertently sending both BTC and B2X funds at the same time. In order to prevent this, developers must implement a protection mechanism into their software which prevents replays from occurring.
Bitcoin Segwit2x does not have any built-in replay protection, but Coinbase has implemented our own replay protection system. You can safely send any BTC or B2X from Coinbase without worrying about replays on the other chain.