OPEC clinched a deal to curtail oil supply, confounding skeptics as the need to clear a record global crude glut — and prove the group's credibility — brought its first cuts in eight years. Crude rose as much as 8.8% in London.

OPEC will reduce output to 32.5 million barrels a day, Iranian Oil Minister Bijan Namdar Zanganeh told reporters in Vienna Wednesday. The breakthrough deal showed an apparent acceptance by Saudi Arabia that Iran, as a special case, can still raise production.

The Organization of Petroleum Exporting Countries is ditching a pump-at-will policy introduced in 2014 to resume its traditional role as price fixer. The shift — aimed at draining a crude glut that's pushed down prices for two years — will help revive the tattered finances of oil-producing countries and reverberate in markets around the world, from the Canadian dollar to Nigerian bonds to U.S. shale equities.