Crude prices and oil and gas indexes recorded their worst two-week performance on record, pummeled by an oil price war and expectations for lower fuel demand as efforts to mitigate the COVID-19 pandemic grind global commerce into low gear.

U.S. West Texas Intermediate crude futures settled at $20.37 per barrel on March 18, tumbling 56.5% over the course of 10 consecutive trading days. The plunge marked the largest decline since the WTI contract started trading in March 1983, according to an analysis of S&P Capital IQ data.

Prior to this year, WTI's steepest two-week drop ⁠— 34.5% ⁠— occurred at the outset of the international campaign to expel Iraqi forces from Kuwait during the Gulf War in January 1991.

WTI is also on pace to surpass U.S. crude oil's 33% drop in January 1986, the largest monthly decline on record based on historical data going back to 1946, according to American Petroleum Institute Chief Economist R. Dean Foreman. WTI is currently down roughly 44% in March.

"It's really like two black swans hitting the oil market simultaneously with a price war at the same time that there's a massive demand shock," said Tamar Essner, director of energy and utilities at Nasdaq Corporate Solutions. "So the degree of oversupply that we're seeing in the market is unprecedented."

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A pair of closely followed oil and gas stock indexes also suffered historic losses during the two-week period through March 18. The S&P Oil & Gas Exploration and Production Index fell 48.3%, while the Alerian MLP Index ⁠— a proxy for pipeline operators and the midstream industry ⁠— sank 59.1%, their worst declines since their launch in June 2006.

Both indexes previously recorded their worst two-week losses in September 2008 as Wall Street firms collapsed during the financial crisis.

The losses cap an extraordinary two weeks in the oil market. Crude prices were already under pressure when a three-year alliance between OPEC and other producer nations led by Russia suddenly collapsed.

The coalition unraveled after Moscow refused to cut production to bolster oil prices. Soon after, top OPEC producer Saudi Arabia vowed to cut its selling price and boost output, a strategy meant to punish Russia by flooding the market and crushing the cost of crude.

This is all occurring against the backdrop of a looming global recession as borders close, travel grinds to a halt, citizens self-isolate and consumer-facing businesses like restaurants and theaters shutter amid the COVID-19 pandemic.

Essner expects the Saudi-Russian standoff to last for at least several months, pushing some U.S. shale producers into bankruptcy and forcing some asset sales, but bringing most mergers and acquisitions to a halt. However, she said, the uncertainties are numerous and include the Trump administration's ability to convince its Saudi allies to wind down the price war, along with measures the White House and banks could take to alleviate financial pressure on U.S. shale drillers.

In Essner's view, the market is underestimating shale oil's critical role in the economy and foreign security, as well as President Donald Trump's incentive to prevent its collapse.

"You see that priced into the equities," she said. "They're completely discounting that and they're focused on the possibility that we'll basically go to zero ⁠— because that's what it would take to shut in production."

Rob Thummel, a portfolio manager at Tortoise Capital focused on energy infrastructure, said many investors will feel compelled to buy yield-oriented stocks with fee-based revenues coming out of a recession. He believes energy infrastructure equities with solid balance sheets and enough cash flow to pay out dividends will likely look attractive.

"The U.S. possesses the largest infrastructure network in the world. Obviously [coronavirus] is going to put a shock to the current demand, but longer-term, when demand comes back you're going to need a lot of infrastructure and the cash flows of these companies has proven to be resilient," he said.

Still, Thummel cautioned that it is difficult to call a bottom for oil, even though current prices are unsustainable.

"Nobody knows how long it's going to stay here," he said. "There's obviously a price war you could fight for a while if you want, but there's no doubt it's going to be difficult staying here for a long, long time because it doesn't make sense for anyone."