Sachs, which had predicted sharp increases in oil prices this year, cut forecasts for benchmark and Brent crudes Tuesday. The investment bank says energy demand growth will slow down as Europe's debt crisis raises the specter of a second recession.
Benchmark crude dropped for the third day, giving up $1.73 to $75.88 a barrel in New York. Brent crude fell below $100 per barrel for the first time since August. It lost $1.97 to $99.74 in London.
Meanwhile, gasoline prices dropped nearly a penny overnight to a new national average of $3.408 per gallon.