Dealertrack Technologies Inc., a Lake Success company that makes software for auto dealers, lenders and manufacturers, said it swung from a loss to a profit in the third quarter from the period last year.

The company said net income for the quarter ended Sept. 30 was $5.8 million, or 13 cents a share, compared to a loss of $2.9 million, or 7 cents a share, for the same quarter last year. The loss last year resulted from the reversal of a tax benefit realized a year earlier and a change in the valuation of a warrant to purchase securities.

advertisement | advertise on newsday

The profit in this year's quarter came on a 26 percent increase in revenues, to $124.6 million, due to strong new and used car sales. Also adding to revenues were two acquisitions that closed Oct. 1 -- of Customer Focused Marketing Inc., an Irving, Texas, provider of customer relations management and marketing services, and VINtek, a Philadelphia provider of automotive collateral management and finance processing services.

Dealertrack also Tuesday updated its 2013 guidance for investors, increasing projected revenues to between $477 million and $480 million, up from prior guidance of $464 million to $468 million, reflecting increased auto sales in the first nine months of the year and expectations that the last two months of 2013 also will be strong.

But it said net income is expected to be between $7 million and $9 million, a decrease from prior guidance of $10 million to $12 million, reflecting the costs of the two acquisitions.

Per-share income is expected to be between 15 cents and 20 cents, down from between 22 cents and 27 cents. The company employs about 1,800 people, including about 300 on Long Island.