The auction houses across all regions will be closed for good on Tuesday, March 18th at approximately 3 AM PT. This shutdown ought not to interfere with your normal playing routine, never mind that you are a night owl who puts Dracula to shame for the amount of time spent awake at night. It will happen at exactly the same time as the scheduled maintenance for the Americas.
Having said that, the slew of sales on the auction house at the time of the shutdown will then expire. As items will be sent out to the highest bidders, should the issue of a bidder-less item arise, then said item would be returned to the seller. All unclaimed equipment or gold can also be found in the “Completed tab” for the auction house.
Despite the “Completed” tab of the auction house having a cap of 50 items, should there be any other additional items around, those are stored in a backlog. These backlog items will then appear as you begin to clear out all of the first 50 items displayed. No auction house? No problem, there’s always Reaper of Souls to look forward to.