InfoSpace ( INSP) posted better-than-expected fourth quarter numbers, but its shares dropped 2% after the resignation of its chief financial officer.

The wireless company made $38 million, or $1.13 per share, for the quarter ended Dec. 31, compared with $19 million, or 50 cents, a year earlier. Latest-quarter results included a tax benefit of $25 million, or 74 cents a share. Profit excluding this one-time event was $12.9 million, or 39 cents. Sales gained 9% to $86.5 million. Analysts surveyed by Thomson First Call were looking for a 27-cent profit on sales of $85 million. 

But Chief Financial Officer David Rostov, who joined the company in April 2003, is resigning to "pursue other interests,'' the company said in a postclose press release. Further details were not provided in InfoSpace's earnings release and a company spokesman couldn't immediately be reached for comment.

The company expects first-quarter revenue of between $85 million and $87 million, in-line with analysts' estimates of $85.4 million. But InfoSpace expects to make between 3 and 6 cents a share where analysts were looking for 21.

InfoSpace fell 48 cents to $23.86 in after-hours trading.