O'Reilly Automotive ( ORLY), an auto parts retailer, said its fourth-quarter earnings rose 79.6% from the year-ago period, boosted by higher sales and improved profit margins. The company earned $39.5 million, or 35 cents a share, in the quarter, compared with $22 million, or 20 cents a share, a year ago. Adjusted for stock option expense, earnings were 36 cents a share in the most recent quarter. On that basis, analysts surveyed by Thomson First call were expecting earnings of 30 cents a share. Fourth-quarter revenue rose 20.4% from a year ago to $515 million. Analysts were expecting revenue of $507.7 million in the most recent quarter. "We are pleased with the strong results this quarter and for the full year 2005," the company said. "We are proud of the continued hard work and dedication of Team O'Reilly that enabled us to achieve comparable store sales growth of 7.5% while also improving our operating margin to 12.3%." "In the fourth quarter of 2005, we opened 38 new stores and continued our successful integration of Midwest Auto Parts. We expect to add 170 to 175 new stores in 2006 as well as a new distribution center in Indianapolis, Indiana that will support our expansion in this region," the company said. Fourth-quarter gross profit rose 24.4% to $231.4 million and gross margin increased 143 basis points to 44.9%. Operating income rose 75.1% to $63.2 million, and operating margin increased 383 basis points to 12.3%.