For the quarter, AutoZone net income gained 7% to $132.5 million compared with $123.88 million posted in the same period last year on sales of parts with high profit margins.

Earnings rose 17.4% to $2.02 per share from $1.73 per share a year earlier.

Shares of AutoZone soared 19.4% or $20.93 to $128.80 at close Tuesday, on the earnings that stood at the top end of market predictions.

Analysts polled by Thomson Financial estimated first quarter earnings per share of $1.91.

For the quarter, gross profit, as a percentage of sales was 49.9% against 49.2% reported same period last year. The company said higher gross margins were a result of category management strategies and the shift in sales mix to higher margin categories.

GAAP inventory rose 8.9% over the same period last year. However, adjusted inventory per store, which includes supplier owned pay-on-scan inventory, rose below 1% to $507 000 from $503 000 last year.

During the quarter, AutoZone repurchased 2.9 million shares for $350 million, or about $121.00 per share. The company will spend a further $108 million on share buybacks in the ensuing quarter.

AutoZone opened 40 new stores, operating a total of 3,972 stores by the quarter''s end. In Mexico, it operated 124 stores.

Operating expenses, as a percentage of sales rose to 33.6% from 33.2% last year due to higher occupancy costs.

Analysts expect second quarter earnings of $1.61 per share on revenues of $1.35 billion. For the year, revenue is estimated at $6.51 billion on sales growth of 5.5%. In the second quarter sales are expected to rise 3.7%.

After hours Wednesday, AutoZone shares were up 0.22% or $0.28 at $126.50. Over the past 52-weeks, the stock has traded in the range $103.40 to $140.29. Analysts are targeting a one-year price of $125.30.

""""As our operating model continues to be strong, we will maintain our disciplined approach to growing operating earnings and utilizing our capital effectively,"""" said Bill Rhodes, the company''s chairman, president and chief executive officer.

AutoZone is a retailer and distributor of automotive replacement parts and accessories in the United States. Each store carries an extensive product line for cars, sport utility vehicles, vans and light trucks, including new and remanufactured automotive hard parts, maintenance items, accessories, and non-automotive products.