Sales and earnings slumped at Sigmatel ( SGTL) in the second quarter, despite a huge tax benefit that kept the company from posting red ink as analysts had anticipated. The audio and multimedia chipmaker predicted another unexpected profit in the third quarter, thanks to the sale of one of its product lines. Excluding the proceeds from that sale, however, the company predicted that it will likely post a wider-than-anticipated loss in the current period. Still, investors cheered the results. In recent trading, Sigmatel shares were up 69 cents, or 18%, to $4.54. In the quarter ended June 30, Sigmatel earned $2.9 million, or 8 cents a share. Net earnings were down 73% from the year-ago period, when the company earned $10.9 million, or 29 cents a share. But the company's bottom line was boosted by a $19.3 million tax benefit that it recorded in the quarter. The benefit included a onetime windfall of $9.3 million, which the company said was the result of a change in its international tax structure. Excluding the one-time gain as well as charges for amortization and stock options, the company would have lost $3.3 million, or 10 cents a share. Sales fell 37% year over year to $43.8 million. Analysts polled by Thomson First Call were expecting the company to lose 51 cents a share in the quarter, not including amortization and stock-options costs, on sales of $42.1 million. In April, Sigmatel forecast a second-quarter loss of 59 cents to 66 cents a share -- or 50 cents to 57 cents a share, excluding options and amortization costs -- on sales of between $40 million and $46 million. It was unclear whether either analysts or Sigmatel had factored the full tax benefit into their forecasts.