U.S. oil futures fell on Thursday, suffering a loss for a ninth straight session and marking their entrance into a bear market, down more than 20% from their recent high on Oct. 3, according to Dow Jones Market Data. December West Texas Intermediate oil CLZ8, -1.61% lost $1, or 1.6%, to settle at $60.67 a barrel on the New York Mercantile Exchange. Traders have become increasingly concerned over the potential for a supply glut as major producers such as Saudi Arabia, Russia and the U.S. had been boosting supplies in the run up to U.S. sanctions on Iranian oil. Sanctions were expected to tighten the world’s oil supplies, but as they kicked in this week, Washington granted eight countries temporary waivers–allowing them to continue buying Iranian oil.

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