As of 21 December at 02:36 UTC, the Mark Method for ACEUSDTZ23 was changed to Fair Price marking. This was possible, as we have now constructed a robust index that represents the spot prices of ACE. ACE is now priced on the .BACET index which incorporates ACE prices from Binance, OKX and LBank. Please note that this also means that Limit Down and Limit Up price protections have been removed. If you have any questions please contact Support.