(CBS) — Oil prices plunged more than 5 percent on Wednesday, testing three-month lows, after U.S. crude inventories rose much more than analysts expected.

“The initial reaction after the EIA’s report was fairly muted, it wasn’t until later in the afternoon that the crude oil plunge really started picking up steam,” Patrick DeHaan, senior petroleum analyst at GasBuddy.com, tells WBBM’s Andy Giersher.  “The biggest glaring factor is that U.S. inventories hit a new all-time record high.”

He also noted oil and gasoline markets have de-coupled, and Wednesday’s big drop will do little to lower current gas prices.