Auto retailer CarMax Inc. (KMX) on Monday reported record quarterly sales and said used-car sales had strengthened since the spring and summer.

CarMax shares fell, however, after the company's same store used-unit sales came in at the low end of an earlier forecast, an analyst said.

CarMax said total sales increased 13 percent to $1.22 billion in the third quarter ended Nov. 30, up from $1.07 billion a year earlier.

Used vehicle sales at stores open more than a year rose 2 percent for the quarter, according to CarMax, which said it sees third-quarter earnings of about 17 cents per share.

That was in line with a forecast of 17 cents or 18 cents per share, which CarMax issued on Nov. 16.

The 17 cents would include a benefit of 1 cent per share from the valuation of securitized receivables interest, the company said.

CarMax, which will release its third-quarter earnings on Dec. 17, said it plans to expand its used-car superstore base by about 16 percent in the year ending on Feb. 26, 2006.

Shares of CarMax, which mostly sells used cars, were down $1.06, or 3.7 percent, at $27.05 in late-morning trading on the New York Stock Exchange (search).

Analyst William Armstrong of C.L. King & Associates said that was partly because the company's same store used-unit sales came in at the low end of the forecast it provided on Nov. 16.

"The stock has had a huge run in the last month or so, so I guess I'm not surprised that it's selling off," Armstrong said.