At 23:02 UTC on 15 April 2017, one constituent of our .BXBT Index, GDAX, reported a trade print of $0.06 / XBT. This fed into the .BXBT Index and caused the price to temporarily move down to $888.48 / XBT which led to a number of users having their positions liquidated.
This was not a BitMEX engine or pricing issue. However, we strive to create a fair platform where users are not unfairly disadvantaged due to an error on another exchange, even if this error was an official price. As such, BitMEX will be refunding those users who were unfairly liquidated due to the pricing discrepancy from GDAX out of our own company funds.
Those users who had their positions liquidated will see the loss between $1183.00 / XBT and their liquidation price transferred back to their BitMEX Bitcoin wallet. Positions lost due to liquidation will not be reinstated.
For the time being, GDAX will be weighted at 0 in the .BXBT index until we have built in sufficient outlier protections.