U.S. Steel ( X) was skidding more than 6% Tuesday after the firm reported worse-than-expected third-quarter earnings.

For the three months ended Sept. 30, U.S. Steel earned $269 million, or $2.27 a share, down from $417 million, or $3.42 a share, in the same period a year earlier.

The results were affected by nonrecurring items in both periods. When excluding unusual charges, the company had a profit of $2.50 a share in the latest third quarter vs. $3.59 a year ago. On average, analysts had been expecting earnings of $2.63 a share this year.

Sales edged up to $4.35 billion in the 2007 quarter from $4.11 billion a year earlier.

"We made good progress in implementing a unified business model for our Tubular segment and are realizing synergies from the Lone Star acquisition," said CEO John Surma in a prepared statement.

Even so, traders were unimpressed and quickly marked down the stock.

Prices per ton of steel sold rose year over year in Europe, while those of flat-rolled products and tubular items fell. Total steel shipments edged up marginally to total 5.56 million tons from 5.55 million in the same period a year earlier.

"We expect a decline in overall results for the fourth quarter mainly due to normal seasonal effects and several scheduled blast furnace outages," Surma added.

During the quarter, U.S. Steel repurchased 285,000 shares at a cost of $28 million. Recently, the stock was down $7.17 to $105.33.