Natural gas is a fossil fuel that originates from the remains of plants and animals that lived many millions of years ago. As a result of being exposed to extreme heat and pressure the once living organisms are transformed into natural gas. The essential commodity is used extensively throughout the U.S. to heat homes as well as in commercial and industrial applications. NGAS is the trading classification of natural gas. It's commonly measured in MMBtu, with 1 MMBTu equaling 1 million BTU (British Thermal Units). Natural gas prices are mainly a function of market supply and demand. Due to limited alternatives for natural gas consumption or production, even small changes in supply or demand over a short period can result in huge price movements. The increase in supply tends to pull prices down, while decreases in supply tend to push prices up. On the other hand, higher demand tends to lead to higher prices, while lower demand can result in lower prices. Other factors that affect natural gas prices include; weather conditions, economic conditions, crude oil price fluctuations, natural gas storage and competition with other fuels like coal and petroleum.