NEW YORK ( TheStreet) -- HP ( HPQ) shares tanked 8.04% to $23.34 in premarket trading as investors digested the tech giant's third-quarter results, released after market close on Wednesday. The Palo Alto, Calif.-based company reported revenue of $27.2 billion, down from $29.7 billion in the prior year's quarter. Analysts surveyed by Thomson Reuters were looking for sales of $27.29 billion. Excluding items, HP earned 86 cents a share, down from $1 a share in the same period last year, and in line with analysts' expectations. HP's numbers, however, felt the effects of a tough PC environment. The company's Personal Systems revenue was down 11% year over year, while Printing revenue fell 4% over the same period. Revenue from the firm's Enterprise Group tumbled 9%. Microsoft ( MSFT) gained 1.52% to reach $32.09 before market open. Early on Thursday, Nomura Equity Research upgraded Microsoft to "buy," citing the potential for shareholder activism at the software giant. "Frustrated Shareholders could support change at Microsoft," wrote Nomura analyst Rick Sherlund, in a note. "Fundamentals are still on a slippery slope as tablets erode PC's, but stable enterprise business and strong cash flows could support a potential activist agenda for large share repurchase, substantially greater dividend and management succession plan." Sherlund noted that ValueAct owns less than a 1% position in the company, but "is likely to have support of shareholders weighing in on their side as they press for a Board seat and attempt to drive greater shareholder value." Microsoft was also one of the most active premarket Nasdaq stocks on share volume of 91,843. Yahoo! ( YHOO) was another winner, rising 1.81% to $27.55 on share volume of 44,302, while SiriusXM ( SIRI) gained 0.82% to $3.69. Electric car maker Tesla ( TSLA) was a more modest gainer, rising 0.34% to $148.37, while Apple ( AAPL) was up 0.25% to $503.62. Facebook ( FB) shares were unchanged at $38.32, although the social networker was one of the most active Nasdaq stocks at 94,118. --Written by James Rogers in New York. Follow @jamesjrogers >To submit a news tip, send an email to: firstname.lastname@example.org.