Thursday's Tech Winners & Losers

Updated from 2:34 p.m. EDT

Motorola (MOT) helped to lift the tech sector Thursday, rising after a Wall Street research firm upgraded the stock and lifted its price target on the cell-phone maker's shares.

Lehman Brothers took its rating on Motorola to overweight from equal weight and boosted its target price to $20 from $18.50, saying the Schaumburg, Ill., company should be improving its spending. Shares of Motorola closed up 1.7% at $16.75.

Another stock on the rise was Sigma Designs (SIGM), a Milpitas, Calif., semiconductor and software company. Sigma's shares gained 10.5% to close at $42.70 after its latest quarterly results and forecast.

For the second quarter, revenue rose 18% to $42.5 million. The company earned $8.6 million, or 32 cents a share, up from last year's $216,000 and 1 cent a share. Excluding items, adjusted earnings climbed to 48 cents a share from 9 cents last year.

Looking to the third quarter, Sigma expects a continued increase in demand for its products and said net revenue should grow more than 20%.

Elsewhere, Microsoft (MSFT) said it will acquire Chicago-based Parlano, the maker of MindAlign, an application for group Internet chats. Microsoft plans to add Parlano's group chat functionality as a new feature for Microsoft Office Communications Server and Microsoft Office Communicator.

Shares of the Redmond, Wash., software giant closed down 0.5% at $28.45.