New York: The dollar firmed against other major currencies on Friday after oil-producing cartel Opec kept its output quota unchanged despite abundant global supplies that have sent crude oil prices plunging.

The decision by the Organization of the Petroleum Exporting Countries at a meeting Thursday in Vienna roiled markets, hammering energy-related US stocks. The price of US benchmark Texas crude plunged more than $7 to a five-year low, and Brent sank to a new four-year low.

Opec had not been expected to respond aggressively to a roughly 35 per cent drop in oil prices since June. But the cartel did less than many experts predicted, opting not even to promise to stop pumping above its current 30 million barrels per day production ceiling.

“The Russian rouble, Norwegian krone and Canadian dollar — all ‘oil sensitive’ currencies — are weaker, the latter even as Canada’s Q3 GDP was firmer than expected,” said Nick Bennenbroek, head of currency strategy at Wells Fargo Securities.

On Friday, a large number of US investors were absent from the foreign-exchange market, as they extended Thursday’s Thanksgiving Day holiday into a long weekend.