The Latest Sign That Coal Is Getting Killed

Coal is having a hard time lately. U.S. power plants are switching to natural gas, environmental restrictions are kicking in, and the industry is being derided as the world's No. 1 climate criminal. Prices have crashed, sure, but for a real sense of coal's diminishing prospects, check out what's happening in the bond market.

Bonds are where coal companies turn to raise money for such things as new mines and environmental cleanups. But investors are increasingly reluctant to lend to them. Coal bond prices tumbled 17 percent in the second quarter, according to an analysis by Bloomberg Intelligence. It's the fourth consecutive quarter of price declines and the worst performance of any industry group by a long shot.