Upheaval in Iraq could throw the world's remarkably stable oil market out of balance, threatening a delicate equilibrium that has kept prices steady for much of the last four years.
Iraqi oil production is at risk because of the outbreak of violence involving militant groups who seized two cities this week and have pledged to march on Baghdad. For now, the fighting is mostly in Iraq's north, away from important oil-producing regions in the south. But the turmoil sent the price of Brent crude, the key international benchmark up to its biggest gain since August. (AP)