Neither. They are based on your current location. Even while in hyper, the server maintains knowledge of your relative position in the galaxy. That is to say, where you would be if you aborted hyperspace at that moment. This is necessary for aborting, and for the Interdictor to work.
"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Interesting...I knew that the server maintained that info, just didn't know it was applied for the market.
(Despite a bug report I created, I can see my hyperspace location under certain circumstances.)