Crude storage is soon to see the drop that filled the cup.
Storage is near capacity constraints, bringing a lot more volatility to the market, Jeffrey Currie, global head of commodities research at Goldman Sachs, told CNBC's "Closing Bell" on Monday.
"When we look at these storage levels in Cushing, Oklahoma, which is where the Nymex prices, there's about 3 million barrels of spare storage capacity, which is nothing in the grand scheme of things," he said. "The fact that we saw cash prices separate from forward prices, tells us that we broke the cash-and-carry arb."
The oversupplied market may see more crude adding to the glut, as Iraq's Oil Ministry told Reuters on Monday that it looks to beat last year's record output, in 2016.
After the news, fears of oversupply crawled into the market and WTI fell 5.75 percent, breaking a two-day winning streak (where it gained nearly 14 percent), to close at $30.34.