The article talks about companies that buy and sell physical commodities and commodity derivatives. These companies can specialize in a few commodities or have a wide-ranging business. They may be part of a group that produces commodities, with the trading house handling marketing. Sometimes, these companies also trade in derivatives. The article discusses why commodity trading houses trade in derivatives and how they do it. It also looks at the regulations that apply to these companies and why they may be regulated as financial services in some countries.