For U.S. shale drillers, the crash in oil prices came with a $26 billion safety net. That’s how much they stand to get paid on insurance they bought to protect themselves against a bear market -- as long as prices stay low.

The flipside is that those who sold the price hedges now have to make good. At the top of the list are the same Wall Street banks that financed the biggest energy boom in U.S. history, including JPMorgan Chase & Co., Bank of America Corp., Citigroup Inc. and Wells Fargo & Co.

While it’s standard practice for them to sell some of that risk to third parties, it’s nearly impossible to identify who exactly is on the hook because there are no rules requiring disclosure of all transactions. The buyers come from groups like hedge funds, airlines, refiners and utilities.

“The folks who were willing to sell it were left holding the bag when prices moved,” said John Kilduff, partner at Again Capital LLC, an energy hedge fund in New York.

The swift decline in U.S. oil prices -- $107.26 on June 20, $46.39 seven months later -- caught market participants by surprise. Harold Hamm, the billionaire founder of Continental Resources Inc., cashed out his company’s protection in October, betting on a rebound. Instead, crude kept falling.

Counterparty Names

Other companies purchased insurance. The fair value of hedges held by 57 U.S. companies in the Bloomberg Intelligence North America Independent Explorers and Producers index rose to $26 billion as of Dec. 31, a fivefold increase from the end of September, according to data compiled by Bloomberg.

Though it’s difficult to determine who will ultimately lose money on the trades and how much, a handful of drillers do reveal the names of their counterparties, offering a glimpse of how the risk of falling oil prices moved through the financial system. More than a dozen energy companies say they buy hedges from their lenders, including JPMorgan, Wells Fargo, Citigroup and Bank of America.

Danielle Romero-Apsilos, a Citigroup spokeswoman, said the bank actively hedges and manages its risk. Representatives of JPMorgan, Wells Fargo and Bank of America declined to comment.

At the end of 2014, JPMorgan had about $671.5 million worth of derivatives exposure to five energy companies, including Pioneer Natural Resources Co., Concho Resources Inc., PDC Energy Inc. and Antero Resources Corp., according to company records. That’s the amount JPMorgan would have owed if the contracts were settled Dec. 31, not including any offsetting trades the bank made.