Just four shale drillers - Exxon, Chevron, Occidental, and Crownquest - can drill new wells at a profit at $31 per barrel of West Texas Intermediate.
The problem is the nature of shale oil wells: while quick to start production and expand it, they are also quick to run out of oil, so drillers need to keep drilling new ones to maintain production, which is what U.S. shale patch players have been doing for years.
However, this has affected investor returns, Bloomberg notes, and now it is affecting spending plans.
"Companies should not be burning capital to be keeping the production base at an unsustainable level," Tom Loughrey from shale oil data company Friezo Loughrey Oil Well Partners LLC told Bloomberg.
"This is swing production -- and that means you're going to have to swing down."