Enron's fall from grace appears to have happened dizzily fast.

In just over 15 years, it turned itself from a regulated natural gas company into one of the world's largest energy traders.

Enron was formed from the merger in 1985 of Houston Natural Gas and InterNorth.

The Texan company is largely credited with creating market trading in energy, allowing energy to be traded in the same way as other commodities such as oil.

Trading in power

With more than 21,000 employees around the world, its revenues were over $100bn in 2000.

Enron grew rapidly, containing three businesses - energy, wholesale and global services.

Enron established itself in the UK at the first signs of energy liberalisation, becoming the first company to begin construction of a power plant after the electric industry was privatised.

As recently as 14 August 2001, Fortune magazine tipped the firm as one of the 10 growth stocks to last the decade

The company has won a string of awards, including Fortune's "America's most innovative company" award for an unprecedented six years between 1996 and 2001.

Among its innovations, it has prised open the German power and gas markets, created a virtual gas storage facility in the UK, and pioneered the world's largest online commodity trading site.

In 2000, it won the Financial Times's "energy company of the year" award and "boldest successful investment decision".

Enron's prominence came not only from the key role it played in world energy markets but also because under President Bush, the US administration looked to its chairman Kenneth Lay for advice on energy.

By some estimates, it had many millions of investors through the holdings of pension funds across the US.

Obscured by investigation

These revenues have now largely been obscured by the accounting tricks, which have seen it become the subject of US investigations and a takeover target for a much smaller company.

In the run up to the collapse of the deal with Dynegy, Enron's core trading business deteriorated as trading partners proved reluctant to deal with a company that could go bankrupt.

"While it is regrettable to see a leading industry player in difficulties, this does not reflect a failure of the merchant energy business," Dynegy chairman and chief executive officer Chuck Watson said.