Market capitalisation: $113 billion
A product of Gorbachev's perestroika reforms, Gazprom has emerged as a global energy giant in the past decade. Formed in 1989 as the successor to the Sovet Union's Ministry of Gas, the company has always been synonymous with the Russian state.
In 1992 Russian president Boris Yeltsin appointed Gazprom's chairman, Viktor Chernomyrdin, as his prime minister. By 1994 the company was owned by a combination of ordinary citizens, employees and the state. Indeed, some 747,000 Russians took up the offer to become Gazprom shareholders.
Things changed radically in 2000 where, in response to asset-stripping by Chernomyrdian and other board members, new president Vladimir Putin reasserted the state's control of the company. Chernomyrdin's shadowy gas-trading company, Itera, was forced to sell the assets it had stripped from Gazprom back to the company, while Putin acolytes Alexei Miller and Dmitri Medvedev were put in charge of the company.
In 2006 Gazprom, by now majority owned by the state, was granted exclusive rights to export Russian gas overseas, assuring its status as a global behemoth. Meanwhile, disputes with Ukraine and Belarus over prices and unpaid debts have shown the clout the company has as an instrument of Russian foreign policy.