The amount charged over spot price for bullion coins and bars. The current spot price, which is the current price per ounce on the world's commodity markets, be £100 for a silver bar but once the premium is added the buyer might pay £120. The premium is calculated according to several factors such as the type of bullion, how much in demand it is according to current market trends, the amount being offered for sale or bid upon, the seller's objectives and economic conditions. Different products carry different premiums based on production costs, for example – it's much cheaper to mint one 100oz bar than 100 individual 1oz coins. Similarly, if a metal is in demand at present or is rare, like platinum and palladium, the premium may be higher.