Brazil's huge oil reserves fuel largest-ever share offer

SAO PAULO, Brazil - The exploration and production of Brazil's huge offshore oil reserves is the driving force behind the globe's biggest-ever share offering.

Petroleo Brasileiro SA, or Petrobras, the nation's state-run energy company, raised $70 billion late Thursday through the sale of more than four billion common and preferred shares in Brazil and the United States. Investors took the opportunity to invest in one of the world's fastest-growing regions for energy production.

The money will finance Petrobras' ambitious $224 billion, five-year plan to develop offshore fields the company discovered in the last three years that hold more than 50 billion barrels of recoverable oil.

If successful, Petrobras will vault itself and its country into the top tiers of world oil and gas producers. Yet some analysts are concerned that the cost, and an increased role for the Brazilian government, could dampen eventual returns for shareholders.