U.S. crude is on a path to $42 a barrel as speculators give up their efforts to drive the commodity higher, according to John Kilduff, founding partner at energy hedge fund Again Capital.

Kilduff, a longtime bear and skeptic of OPEC's deal to curb production, said oil's more than 5 percent plunge to roughly three-month lows on Wednesday was the final nail in the coffin for speculators. The high trading volume indicates they are selling out of their bullish positions, he said.