Just a slight add on to what I said.
In my FCOM it says that on the HOLD page, down the bottom right where it says "best speed"
Displays computed best holding speed based on present altitude and conditions.
Note: May exceed maximum speed permitted by regulatory agency.
What I want to know is, best for what? Endurance? Avoiding a stall? Getting around the hold quickly? I imagine it is related to endurance but I would like to know if it is min drag for those conditions. ANyone know?