Thursday's Tech Winners & Losers

Updated from 11:48 a.m. EDT

Shares of WebMethods(WEBM Quote) were among technology's winners Thursday, soaring 27.2% after the software company agreed to be acquired by Software AG for $546 million, or $9.15 a share.

The all-cash deal represents a 26% premium to WebMethods's closing price of $7.28 on Wednesday. "Combining our product portfolio and sales team with those of WebMethods gives us a major foothold in the critical North American market," Software AG said. The deal is expected to close during the second quarter. Shares closed up $1.98 to $9.26.

Rackable Systems(RACK Quote) slumped 15.6% after the server-maker warned that it would post a first-quarter loss. The company now sees gross margin falling 30% lower than its previous forecast. Rackable blamed the gross margin pressure on an "intensity of competition" in its largest accounts.

The company also expects higher operating expenses, which are due, in part, to one-time charges associated with the cancellation of an order from a customer. Expenses also will be higher because of severance charges and charges related to sales and use-tax exposures from past sales to various customers. The company still expects to post revenue of $70 million to $75 million. Analysts polled by Thomson First Call project earnings of 5 cents a share on revenue of $73.8 million. Shares closed down $2.64 to $14.24.

Shares of Vocus(VOCS Quote) jumped 17.2% after the software company priced a follow-on stock offering at $19.50 a share. The company sold more than 3 million shares in the offering, an increase of about 192,000 shares over its initial filing. Some 1.8 million shares were sold by selling shareholders while the rest were sold by the company. Thomas Weisel Partners led the underwriting syndicate. Shares closed up $3.36 to $22.89.