Seaport Global Securities LLC ended coverage of Cloud Peak Energy Inc. after the pure-play Powder River Basin coal miner said in a March 15 securities filing that it might file for Chapter 11 bankruptcy within a month.

Cloud Peak elected not to make a $1.8 million interest payment that was due March 15, triggering a 30-day grace period before the company would default and accelerate the maturity of the debt. The filing said Cloud Peak does not have adequate liquidity to repay the principal balance if the debt is accelerated and may seek bankruptcy protection if it cannot make the payment by April 14.

Seaport analysts Mark Levin and Nathan Martin wrote March 15 that they "do not anticipate a buyer of the company's assets to emerge" and expect Cloud Peak's three Powder River Basin mines to continue operating through any potential restructuring process.

"Notably, we think [Cloud Peak] may already be ceding market share to Arch and Peabody as customers are well aware of the company's troubles," the analysts wrote.

Cloud Peak shipped 49.7 million tons in 2018 and is budgeting to produce 50 million tons in 2019, but expects lower pricing and higher costs this year to reduce cash flow.

The company's shares lost about half their value after the filing and opened at 21 cents on March 18.