Before trading began on September 23, auto parts retailer AutoZone Inc. (AZO) released results of the company’s 4Q earnings in which the company’s profits dipped year-over-year. The company incurred increased expenses that affected the bottom-line. Despite the drop in profits, AutoZone saw a huge jump in earnings per share growth over last year’s posting.

AutoZone posted a 4Q profit of $236.1M, or $4.33 per share, a slight decrease from last year’s 4Q earnings of $243.7M, or $3.88 per share. During the period, AZO witnessed a 3.1% decrease in profits, but an 11.6% increase in earnings per share. The company’s per share growth was directly attributed to fewer outstanding shares in their float this year than in last year’s 4Q.

Overall sales during the quarter advanced marginally, increasing from $2.21B a year ago to $2.23B, a 1% jump. Excluding an extra week in sales from last year’s quarter, revenues would have been up 7.2% from the prior year’s tally of $2.08B. Meanwhile, domestic sales from stores opened at least one year increased 5.4% year-over-year.

Within the industry, analysts were looking for AutoZone to book a quarterly profit of $4.45 per share, with overall revenues coming in at $2.23B.

“We are very pleased with our comparable performance for both the fourth quarter and fiscal year 2009. In fiscal 2009, we again expanded our parts assortment, significantly increased the number of markets supported by our enhanced Hub store model, expanded our Commercial sales force, increased formalized training, and leveraged new technologies all primarily focused on customer service improvements.” remarked Bill Rhodes, AutoZone’s Chairman, President and CEO.

Rhodes also stated, “As our sales performance improved, we elected to accelerate the expansion of several of these initiatives to better position us to continue to grow our sales for the future. In fiscal 2009, we experienced market share gains in each of our four businesses. I’d like to thank all our AutoZoners across North America for their dedication and passionate commitment to our customers and our organization. Finally, I’d like to highlight that our return on invested capital increased again ending the year at 24.4%. This performance highlights our commitment to a disciplined approach of increasing operating earnings and utilizing our capital effectively,”

Peeking further inside the company’s report, AutoZone saw their gross profit, as a percentage of gross sales, remain unchanged from last year’s 50.3%. The company confirmed that gross margin would have slipped if it had not been for lower fuel costs and continued leverage in distribution costs, resulting from improved expense efficiencies.

During the period, AutoZone’s operating profits increased marginally year-over-year, advancing from $416.84M a year ago to $417.60M, nearly a 2% gain. Adversely, operating expenses for the quarter grew, increasing from last year’s total costs of $694.97M to $705.46M, a jump in costs of 1.5%.

Additionally, interest expenses for the 4Q jumped from $34.76M to $47.76M, an increase of more than 37%.

For fiscal 2009, AutoZone’s net earnings for the year advanced 2.4% from last year’s tally, climbing to $657.05M from $641.61M. With profits increasing, earnings per share advanced as well, from $10.04 per share a year ago to $11.73 per share. Once again, if excluding the extra week of operation in last year’s results, AutoZone would have posted a 5% increase in net income and a 19.7% increase in earnings per share.

Yearly revenues grew as well, increasing from totals in 2008 of $6.52B to $6.82B in 2009, an increase of 4.6% year-over-year. For the year, same store sales posted a gain also, increasing by 4.4%.

Analysts, on average, were looking for yearly earnings results from the auto parts retailer to be $11.73 per share on overall revenues of $6.81B.

Investors were not impressed with AutoZone’s quarterly performance report. By the sound of the closing bell on September 23, shares of AZO were being pummeled, losing nearly 6%, or $9.02, to conclude the day at $143.90 per share.

During the past year, the company’s stock price has traded within a wide range, reaching highs of $169.99 per share, while dipping as low as $84.66 per share.