Individual users can register up to three BitMEX accounts so long as the accounts in question are all owned by the same person and have been verified. 

Accounts that are verified with the same verification documents are linked during set-up. 


Linked accounts can send funds between other linked accounts instantly with no transaction fees. These transactions are actioned internally at BitMEX rather than over the BTC network.


If you have any questions on this, please contact support.

https://www.bitmex.com/app/support/contact