Crude futures plunged almost 9% and closed below $50 a barrel for the first time in more than three years. The January futures contract, which had more trading volume, also closed down more than 8% to $48.44 a barrel.

Analysts chalk up the collapse in oil prices—now down 67% from summertime highs—to disappearing demand for oil in both developed and developing economies.

But not everybody thinks $40-something oil is here to stay. Oil companies are booking space on supertankers to store oil at sea until prices rebound, Reuters reports. Just stay close to port.