Roughly 6,000 hospitals across the nation are starting to reveal the rates they negotiate with insurers for a number of procedures. The figures show how widely prices vary for the same procedure depending on who is paying, as highlighted by a new Wall Street Journal report.

For example, the report found that a C-section can cost between $6,241 and $60.584 - all depending on which insurer covers it. Niall Brennan, chief executive of the Health Care Cost Institute said: "It is shining a light on the insanity of U.S. healthcare pricing. It's at the center of the affordability crisis in American healthcare."

The rates are a key driver of the massive healthcare costs in the U.S., some of the highest in the world. It was a Trump administration rule that shed light on the differences in procedure pricing - some of the widest gaps in pricing of any U.S. industry. Gerard Anderson, a healthcare economist at Johns Hopkins University, commented: "These price differentials are unique to the healthcare and hospital industry."