The oil market rout has made some investors so bearish they are buying contracts that pay out if prices drop below $40 a barrel — a level last traded during the bleakest chapters of the financial crisis.
The number of options to sell US crude at $40 a barrel by December 2015 was equivalent to 880,000 barrels, after more than quadrupling in the past two weeks, according to CME Group exchange data. Similar options with a $35 a barrel strike price climbed to 669,000 barrels from none.
The option buying took place as West Texas Intermediate crude was tumbling 37 per cent from its June high to $67.38 a barrel on Wednesday, hastened by Opec's recent decision to stay the course on supply.
"It's a punt, a shot at the worst-case scenario for the oil price," said Raymond Carbone, president of broker Paramount Options in New York. "You're a genius if you're right. And if you're wrong, it won't ruin your lifestyle."
US benchmark WTI futures last settled below $40 a barrel in February 2009.
The appearance of the bearish positions does not mean the market will go that low again. Brokers and bankers said the trades were probably low-risk, low-cost "lottery tickets" for a prospective windfall.
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Still, the inability of commodity markets to neatly match rising supplies with lukewarm demand raises the chance of further price declines until drillers cut back.
Potential factors which could drive the oil market towards $35-$40 a barrel include a warm winter in the northern hemisphere that would curb heating fuel demand, or high rates of refinery maintenance in the US Gulf of Mexico oil hub, which would temporarily slow demand for crude, said Jan Stuart, global energy economist at Credit Suisse.
"It's no longer terribly far-fetched to see a scenario that could create, briefly, such a low price," Mr Stuart said. Credit Suisse forecasts WTI at $75 a barrel a year from now.
Industry executives said it was highly unlikely that an oil producer bought the put options, as it would be paying a premium to lock in a loss. Instead they pointed to a speculator such as a hedge fund.
Whoever bought the options has already realised a gain: prices of both the $35 and $40 options contracts have doubled since late November.
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In aggregate, money managers still held three bullish positions for every bearish one in WTI futures and options, according to the Commodity Futures Trading Commission.
The commission took its latest snapshot on November 25, two days before the Opec decision.