Shares of Peabody Energy Corp. fell Thursday after the coal producer reported fourth-quarter profit that fell short of Wall Street estimates.

Net income at St. Louis-based Peabody fell 80 percent to $35.8 million, or 13 cents a share, from $175 million, 65 cents, in the same quarter a year ago, the company said in a statement. Revenue rose 10 percent to $1.21 billion.

The drop in profit mostly reflects the November spinoff of Peabody’s eastern U.S. mining operations into a separate publicly-traded company, Patriot Coal Corp. Peabody recorded a $155.3 million loss in the quarter for costs associated with the transaction.

Excluding costs associated with the Patriot spinoff, the coal producer earned 71 cents a share — 8 cents less than the average estimate of analysts surveyed by Thomson Financial.

Peabody shares fell as much as 12 percent in early trading. At noon, the stock was down $2, or 3.6 percent, on the New York Stock Exchange.