Some of fracking’s biggest skeptics are on Wall Street. They argue that the industry’s financial foundation is unstable: Frackers haven’t proven that they can make money. “The industry has a very bad history of money going into it and never coming out,” says the hedge fund manager Jim Chanos, who founded one of the world’s largest short-selling hedge funds. The 60 biggest exploration and production firms are not generating enough cash from their operations to cover their operating and capital expenses. In aggregate, from mid-2012 to mid-2017, they had negative free cash flow of $9 billion per quarter.

These companies have survived because, despite the skeptics, plenty of people on Wall Street are willing to keep feeding them capital and taking their fees. From 2001 to 2012, Chesapeake Energy, a pioneering fracking firm, sold $16.4 billion of stock and $15.5 billion of debt , and paid Wall Street more than $1.1 billion in fees, according to Thomson Reuters Deals Intelligence. That’s what was public. In less obvious ways , Chesapeake raised at least another $30 billion by selling assets and doing Enron-esque deals in which the company got what were, in effect, loans repaid with future sales of natural gas.

But Chesapeake bled cash. From 2002 to the end of 2012, Chesapeake never managed to report positive free cash flow, before asset sales.

In early 2015, another famous hedge fund manager, David Einhorn, went public with his skepticism at an investment conference. He had looked at the financial statements of 16 publicly traded exploration and production companies and found that from 2006 to 2014, they had spent $80 billion more than they received from selling oil.

A key reason for the terrible financial results is that fracked oil wells show a steep decline rate: The amount of oil they produce in the second year is drastically smaller than the amount produced in the first year. According to an economist at the Kansas City Federal Reserve, production in the average well in the Bakken — a key area for fracking shale in North Dakota — declines 69 percent in its first year and more than 85 percent in its first three years. A conventional well might decline by 10 percent a year. For fracking operations to keep growing, they need huge investments each year to offset the decline from the previous years’ wells.