MEMPHIS, Tenn., March 4, 2014 (GLOBE NEWSWIRE) -- AutoZone, Inc. (NYSE:AZO) today reported net sales of $2.0 billion for its second quarter (12 weeks) ended February 15, 2014, an increase of 7.3% from the second quarter of fiscal 2013 (12 weeks). Domestic same store sales, or sales for stores open at least one year, increased 4.3% for the quarter. Net income for the quarter increased $16.6 million, or 9.4%, over the same period last year to $192.8 million, while diluted earnings per share increased 17.8% to $5.63 per share from $4.78 per share in the year-ago quarter. For the quarter, gross profit, as a percentage of sales, was 52.1% (versus 51.9% for last year's quarter). The improvement in gross margin was attributable to higher merchandise margins and lower shrink expense, partially offset by the inclusion of the recent acquisition of AutoAnything (20 bps). Operating expenses, as a percentage of sales, were 35.2% (versus 34.7% last year). The increase in operating expenses, as a percentage of sales, was primarily due to the timing of advertising costs (22 bps). Under its share repurchase program, AutoZone repurchased 404 thousand shares of its common stock for $200 million during the second quarter, at an average price of $495 per share. Year-to-date, the Company has repurchased 1.082 million shares of its common stock for $492 million, at an average price of $454 per share. At the end of the second quarter, the Company had $727 million remaining under its current share repurchase authorization. The Company's inventory increased 12.0% over the same period last year, driven by a combination of increased product placement and new store openings. Inventory per store was $589 thousand versus $544 thousand last year and $566 thousand last quarter. Net inventory, defined as merchandise inventories less accounts payable, on a per store basis was a negative $74 thousand versus negative $54 thousand last year.