RICHMOND, Va. — CarMax Inc. reported net income of $103 million in the second quarter ended Aug. 31, compared with $14 million in the year-ago period.

The company’s sales increased 13 percent $2.08 billion from $1.84 billion in the second quarter of last year. Comparable store used-vehicle sales increased 8 percent in the second quarter, while new-vehicle sales dropped 19 percent.

Used vehicle gross profit increased to $2,120 per unit from $1,870 per unit in the prior year quarter. The company said the improvement resulted from a combination of factors, including the continued appreciation in used car wholesale values since January 2009, an increase in inventory turns and the robust sales environment experienced in the quarter.

“We are pleased to report healthy increases in both used and wholesale vehicle unit sales,” said Tom Folliard, president and chief executive officer. He added that the federal government’s Cash for Clunkers program created a spike in floor traffic in late July and August and had a beneficial effect on sales.

The company’s auto financing arm, CarMax Auto Finance, reported income of $72.1 million in the second quarter, compared with a loss of $7.1 million in the year ago period, due in part to an increase in the value of bands the company holds.