A commodity broker buys or sells physical commodities, such as agricultural products, minerals, natural gas or oil, or precious metals, on behalf of an investor. They closely follow international markets in a specific commodity or group of commodities and make trades on the trading floor. Duties include developing reports and forecasts. They often work for brokerage firms, and present their research either to their managers or to give their clients trade recommendations. Some commodity brokers may travel to sites where commodities are made or extracted, such as a large farm or a coal mine.