Patriot Coal Corp. (PCX) said it plans to sell about 12 million shares, or 15% of its current outstanding stock, becoming the latest company to offer shares as market appetite returns.

Shares fell 4.15% premarket to $8.55; the stock through Monday was up 43% this year.

Proceeds from the sale will go to pay down debt, a primarily use of the many billions of dollars raised by companies the past month amid the stock market's ongoing rebound and still-constrained credit markets.

If there is sufficient demand, the eastern U.S. coal producer could sell up to 15% more shares. The industry is dealing with falling demand and prices as electricity usage declines and steel output slumps.

Amid the industry weakness, Patriot on Monday slightly cut its 2009 sales outlook to 33.5 million to 35 million tons from 34 million to 36 million tons.

-By Mike Barris, Dow Jones Newswires; 201-938-5658; mike.barris@dowjones.com