Members of the Organization of the Petroleum Exporting Countries agreed to keep production targets unchanged at their meeting in Vienna, sending Brent crude to its lowest level in more than four years.
The decision reflected a strategy of maintaining market share against rapidly growing American shale output rather than cutting supply to support prices. Brent had traded above $110 a barrel as recently as June.
The fall in prices strained the budgets of producer states including Nigeria, Venezuela and Russia, all of which depend heavily on oil receipts for public spending and foreign exchange.
