The Federal Energy Regulatory Commission was established to oversee the US domestic energy markets in 1977. It is part of the US Department of Energy.
Its job is to ensure that fair prices are paid for the transmission of gas and oil and electricity across state boundaries, a job that gained importance as the deregulation of energy markets gathered pace.
But the FERC exempted trading in electricity contracts from its reporting requirements after lobbying from Enron in the 1990s. It also failed to closely examine reports filed by Enron.
Its current chairman is Pat Wood, a close associate of President George Bush.
Mr Wood was the chief energy regulator for the state of Texas before taking up his current post.
Press reports suggest that Enron boss Kenneth Lay suggested his appointment to the Bush administration.