Arbitrage refers to the fast purchase and re-sale of gold, silver, platinum and palladium to take advantage of fluctuating prices. Gold and Silver are two of the most popular and widely traded commodities thanks to their high liquidity. Precious metals arbitrage involves buying and selling quickly to benefit from the difference between the buy and sell price ('bid' and 'ask' price). For example, the gold price on one marketplace may be a few pounds, dollars or euros lower than on another. Traders buy at the low price and immediately sell at the higher price to make a profit.