Why are oil prices falling, again?

One reason is that the largest consumers of crude oil, the United States, is increasing its stockpile.

Oil pumpjacks in the Permian Basin oil field are getting to work as crude oil prices gain. Spencer Platt | Getty Images

Crude oil prices are falling, again.

On Wednesday,  U.S. West Texas Intermediate crude futures plunged $2.13 to $51.15 per barrel, tumbling 4% on the day to a new five-month low. Brent crude, the international benchmark for oil prices, f…