In different deregulation processes the institutions and market designs were often very different but many of the underlying concepts were the same. These are: separate the potentially competitive functions of generation and retail from the natural monopoly functions of transmission and distribution; and establish a wholesale electricity market and a retail electricity market. The role of the wholesale market is to allow trading between generators, retailers and other financial intermediaries both for short-term delivery of electricity (see spot price) and for future delivery periods (see forward price).