The London Gold Price is a clearly posted, quoted price for gold that occurs twice per day.
The objective in establishing this was to allow large quantities of gold to be bought and sold using a single price.
Because this price does not fluctuate and can not be disputed, people in the industry such as gold mines, refiners, jewelry manufacturers, and banks use it as a basis for daily transactions.
Most people in the trade rely on the PM Fix each day. This figure in the basis of all pricing formula's for the next morning's business of buying and selling.