Nationalising Yukos would give Russia the strategic leverage in oil that it enjoys in gas, which the state-controlled monopoly Gazprom sells to nearly all of Russia's neighbours and most of Europe.

ECONOMIST: Putin versus the oligarchs

To keep Petrobras from taking on the negative attributes of a state-controlled monopoly, the government wants a state-owned entity other than Petrobras to govern the energy contracts and manage the oil revenues.

FORBES: Brazil: Strategic Planning For Pre-Salt

Russia's state-controlled gas monopoly Gazprom has reported a big rise in three-month profits.

BBC: Price rises boost Gazprom profits

NTT, the state-controlled telephone monopoly, on corporate communications and data services.

ECONOMIST: Wiring corporate Japan

There are the big Russian energy firms, led by Gazprom, the state-controlled gas monopoly, which control most energy supplies to ex-Soviet countries, and much of the hard currency coming into Russia.

ECONOMIST: Still most awkward partners

The general election game plays out the polling battle on a computer controlled board that is part-Monopoly, part-Trivial Pursuit.

BBC: Playing the politics game

Until Bill McGowan came on the scene in 1974, American Telephone and Telegraph had controlled all aspects of telephony in the United States through its monopoly position.

FORBES: MCI's Bill McGowan Proved That Telephony Competition is Good for Consumers

They receive subsidised loans from state-controlled banks, they are given land cheaply and they usually enjoy a sheltered monopoly or oligopoly.

ECONOMIST: Privatisation in China