Shares of Check Point Software ( CHKP) were among technology's losers Thursday, falling 9% after the security software company put third-quarter sales at the low end of its guidance and narrowed its earnings forecast.

The company now expects earnings of 31 cents to 32 cents a share on sales of $140 million to $141.5 million. In July, the company predicted that it would earn 30 cents to 33 cents a share on sales of $140 million to $150 million. Analysts polled by Thomson First Call had been expecting earnings of 32 cents a share on sales of $146.7 million.

Separately, Check Point said it plans to acquire privately held Sourcefire for $225 million. The deal is expected to close by the end of the first quarter of 2006. Check Point shares recently traded down $2.19 to $21.51.

Viisage Technology ( VISG) surged 46% following news that L-1 Investment Partners would buy a $100 million stake in the company. The newly issued stock is being bought for $5.25 a share, representing a 44% premium to Wednesday's closing price of $3.64. Viisage will use the cash infusion to fund its growth and expansion within the technology identity solutions market, the company said. Viisage also said it will initiate a 1-for-2.5 reverse stock split.

In addition to announcing the reverse split and L-1 investment, Viisage lowered its third-quarter sales forecast. The company now expects sales of $13 million to $14 million, down from previous guidance of $16 million to $20 million. The company said customer delays, budgetary pressures and deferral of previously expected government spending hurt third-quarter results. Shares were trading up $1.66 to $5.30.

Shares of ATI Technologies ( ATYT) rose 7% after the company posted a wider fourth-quarter loss but offered an upbeat first-quarter sales guidance. The maker of graphics chips reported a loss of $103.5 million, or 41 cents a share, on sales of $470.2 million. Excluding an inventory writedown and stock compensation charges, the company would have reported a loss of $29 million, or 12 cents a share. Analysts were expecting a loss of 30 cents a share on sales of $471.4 million, though it's unclear whether analysts were including the writedown or stock expense charges in their forecasts. A year earlier, the company earned $61.2 million, or 24 cents a share, on sales of $572.2 million.

Looking ahead, ATI projected first-quarter sales would grow by about 15% sequentially, implying sales of $540.7 million. Analysts had been expecting sales of $534.8 million. Shares were up 91 cents to $14.17.

Siebel Systems ( SEBL) rose modestly after the software company said third-quarter sales would be above last year's results and top Wall Street targets. The company anticipates reporting sales of about $346 million, up from $317 a year ago, and up from its previous forecast of $305 million to $315 million. Analysts had been expecting sales of $311.3 million. Excluding charges, the company expects operating income of about $46 million. Siebel, which is in the process of being acquired by Oracle ( ORCL), recently traded up 3 cents to $10.34.

Shares of Cognos ( COGN) rose 2% after the company said it would buy up to 4 million shares as part of a stock buyback plan. The company said it won't spend more than $100 million under the program, which is slated to start next week and last for a year. Shares were trading up 84 cents to $38.54.

Other technology heavy traders included Microsoft ( MSFT), up 8 cents to $24.75; Intel ( INTC), down 1 cent to $24.06; JDSU ( JDSU), down 4 cents to $2.21; Cisco ( CSCO), up 12 cents to $17.62; Lucent Technologies ( LU), unchanged at $3.27; Sun Microsystems ( SUNW), up 3 cents to $4.24; Sirius Satellite Radio ( SIRI), down 19 cents to $6.53; Dell ( DELL), down 18 cents to $32.41; Applied Materials ( AMAT), up 13 cents to $16.79; Yahoo! ( YHOO), up 51 cents to $34; and SanDisk ( SNDK), down 54 cents to $51.46.

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