Entrance month futures contracts sometimes converge with spot costs as they close to expiry.

“There will be traders in the market who only want to trade the paper, so they will roll over into the next futures contract. That means selling the May contract and buying the June,” Hynes, who is a senior commodity strategist at ANZ, instructed CNBC in a follow-up e-mail change.

“But there are also traders who are buying for clients who trade the physical. So they hold the contract to expiry and deliver the crude,” or settle for the crude if they’re on the opposite facet of the commerce, he stated.