Image Source: Marathon Oil

After a meteoric rise from the mid-$20s to more than $40 a barrel, crude took a breather this week, ending down 4%, and below $40 a barrel. That took energy stocks down with it, with dozens dropping double digits this week, giving up a portion of their recent gains. According to S&P Capital IQ data, some of the worst-performing energy stocks during this week were California Resources (OTC:CRC), Marathon Oil (NYSE:MRO), Dorian LPG (NYSE:LPG), Denbury Resources (NYSE:DNR), and Bristow Group (NYSE:BRS)

Of that group, only Dorian LPG had any company-specific news to fuel its slump. It was the recipient of an analyst downgrade, which removed its buy rating and slashed its price target on the stock. It did so citing weaker-than-expected conditions in the liquefied petroleum gas-shipping market, which is putting pressure on the value of Dorian LPG's shipping vessels. 

The rest of the week's big movers all slumped on the drop in crude prices, which was largely fueled by a much wider-than-expected build in oil inventories. According to data from the U.S. Energy Information Administration, 9.4 million barrels were added to storage this week, which was nearly triple the consensus estimate of 2.7 million barrels. It's a number that implies that the oil glut isn't yet improving, which is bad news for struggling oil companies like California Resources, Marathon Oil, and Denbury Resources, all of which need higher oil prices to improve their cash flow and their balance sheets.

Meanwhile, offshore services company Bristow Group needs higher oil prices so that offshore producers increase their activity, which would lead to improved business conditions for the company. Given the unexpectedly large rise in oil inventories, an improvement in the oil price to the level these companies need isn't just over the horizon.

To learn more about why these stocks moved so sharply, check out the following slideshow.

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