Tumbling oil prices have exposed a weakness in the insurance that some U.S. shale drillers bought to protect themselves against a crash.

At least six companies, including Pioneer Natural Resources Co. and Noble Energy Inc., used a strategy known as a three-way collar that doesn’t guarantee a minimum price if crude falls below a certain level, according to company filings. While three-ways can be cheaper than other hedges, they can leave drillers exposed to steep declines.

“Producers are inherently bullish,” said Mike Corley, the founder of Mercatus Energy Advisors, a Houston-based firm that advises companies on hedging strategies. “It’s just the nature of the business. You’re not going to go drill holes in the ground if you think prices are going down.”

The three-way hedges risk exacerbating a cash squeeze for companies trying to cope with the biggest plunge in oil prices this decade. West Texas Intermediate crude, the U.S. benchmark, dropped about 50 percent since June amid a worldwide glut. The Organization of Petroleum Exporting Countries decided Nov. 27 to hold production steady as the 12-member group competes for market share against U.S. shale drillers that have pushed domestic output to the highest since at least 1983.

WTI for January delivery rose 78 cents to $54.89 a barrel in electronic trading on the New York Mercantile Exchange at 10:34 a.m. London time.

Debt Price

Shares of oil companies are also dropping, with a 49 percent decline in the 76-member Bloomberg Intelligence North America E&P Valuation Peers index from this year’s peak in June. The drilling had been driven by high oil prices and low-cost financing. Companies spent $1.30 for every dollar earned selling oil and gas in the third quarter, according to data compiled by Bloomberg on 56 of the U.S.-listed companies in the E&P index.

Financing costs are now rising as prices sink. The average borrowing cost for energy companies in the U.S. high-yield debt market has almost doubled to 10.43 percent from an all-time low of 5.68 percent in June, Bank of America Merrill Lynch data show.

Locking in a minimum price for crude reassures investors that companies will have the cash to keep expanding and lenders that debt can be repaid. While several companies such as Anadarko Petroleum Corp., Bonanza Creek Energy Inc., Callon Petroleum Co., Carrizo Oil & Gas Inc. and Parsley Energy Inc., use three-way collars, Pioneer uses more than its competitors, company records show.

‘Best Hedges’

Scott Sheffield, Pioneer’s chairman and chief executive officer, said during a Nov. 5 earnings call that his company has “probably the best hedges in place among the industry.” Having pumped 89,000 barrels a day in the third quarter, Pioneer is one of the biggest oil producers in U.S. shale.

Pioneer used three-ways to cover 85 percent of its projected 2015 output, the company’s December investor presentation shows. The strategy capped the upside price at $99.36 a barrel and guaranteed a minimum, or floor, of $87.98. By themselves, those positions would ensure almost $34 a barrel more than yesterday’s price.

However, Pioneer added a third element by selling a put option, sometimes called a subfloor, at $73.54. That gives the buyer the right to sell oil at that price by a specific date.

Below that threshold, Pioneer is no longer entitled to the floor of $87.98, only the difference between the floor and the subfloor, or $14.44 on top of the market price. So at yesterday’s price of $54.11, Pioneer would realize $68.55 a barrel.

‘Better Upside’

David Leaverton, a spokesman for Irving, Texas-based Pioneer, declined to comment on the company’s hedging strategy. The company said in its December investor presentation that “three-way collars protect downside while providing better upside exposure than traditional collars or swaps.”

The company hedged 95,767 barrels a day next year using the three-ways. If yesterday’s prices persist through the first quarter, Pioneer would realize $1.86 million less every day than it would have using the collar with the floor of $87.98. That would add up to more than $167 million in the first quarter, equal to about 14 percent of Pioneer’s third-quarter revenue.

Exposure Cost

The strategy ensures that the bulk of Pioneer’s production will earn more than yesterday’s market price. The three-ways will also prove valuable if oil rises above the subfloor.

“What they have is much better than nothing,” said Tim Revzan, an analyst with Sterne Agee Group Inc. in New York. “But they left some money on the table that they could have locked in at a better price.”

Noble Energy used three-ways to hedge 33,000 barrels a day, according to third-quarter SEC filings. Assuming yesterday’s prices persist, Houston-based Noble will bring in $50 million less in the first quarter than it would have by locking in the floor prices.

Bonanza Creek, based in Denver, Colorado, set up three-ways with a floor of $84.32 and a subfloor of $68.08, SEC records show. If prices stay where they are, the company will realize $8.1 million less in the first quarter than it would have by just using the floor.

Ryan Zorn, Bonanza Creek’s senior vice president of finance, said that the comparison doesn’t take into account the advantages of the strategy. The proceeds from selling the $68.08 puts helped pay for the protection at $84.32, without which Bonanza Creek would likely have purchased cheaper options with a lower floor.

‘Much Better’

“The other comparison is if we’d done nothing,” Zorn said. “I view it as being much better than being unhedged.”

Representatives for Anadarko, Noble, Carrizo and Parsley didn’t return e-mails and phone calls seeking comment.

“Because we’ve had high energy prices for so long, it could have given them a false sense of confidence,” said Ray Carbone, president of Paramount Options Inc. in New York. “They picked a price they thought it wouldn’t go below. It has turned out to be very expensive.”

Callon’s first-quarter three-ways cover 158,000 barrels with a floor of $90 and a subfloor of $75, company filings show. Callon, based in Natchez, Mississippi, will get $3.3 million less that it would have realized by using the $90 floor, assuming prices stay where they are.

“Certainly, if we’d had the foresight to know prices were going to crater, you’d want to be in the swap instead of the three-way,” said Eric Williams, a spokesman for Callon. “Swaps make more sense if you knew prices were going to go down the way they did, but a few months ago everyone was bullish.”

–With assistance from Ben Sharples in Melbourne and Nabila Ahmed in New York.