The price of gold fluctuates rapidly throughout the course of any trading day. As with any investment, gold prices rise and fall based on the laws of supply and demand. Prices follow supply and demand trends, and those trends change by the minute.
Gold prices do not fluctuate according to a pre-determined monetary value. Instead, prices change based on how much investors are willing to pay for gold and the amount of gold owners are willing to sell. Again, the law of supply and demand affects the sale price of gold during any given trading day. Other factors that affect gold prices include current key interest rates, the value of the U.S. Dollar and the overall health of major market indexes, as of 2015.