NEW YORK ( TheStreet) -- MetroPCS ( PCS) shares, which jumped almost 18% on Tuesday, rose 0.96% to $13.70 in premarket trading as rumors swirled about a possible merger with T-Mobile USA. Shares of HP ( HPQ), which hosts its securities analyst meeting on Wednesday, crept up 0.41% to $17.20. The tech giant, which unveiled its strategy for Software-Defined Networks(SDN) on Tuesday, is expected to provide an update on the company's restructuring effort at the analyst event. Sirius XM ( SIRI) shares rose 0.76% to $2.64 before market open on Wednesday. The satellite radio giant was also one of the most active premarket Nasdaq stocks on share volume of 173,715. Research In Motion ( RIMM), however, was a loser, slipping 1.45% to $8.15 on share volume of 173,346. Security specialist Sourcefire ( FIRE) saw its shares rise more than 2% to $49.05 shortly after market close on Tuesday when the firm announced preliminary third-quarter results. The Columbia, Md.-based firm predicted revenue and adjusted earnings slightly above the high end of its guidance. In July, Sourcefire forecast third-quarter revenue between $54 million and $56 million and adjusted net income of 19 cents to 21 cents a share. On Tuesday, Sourcefire also announced the retirement of CEO John Burris, who had been on medical leave. Martin Roesch, the company's chief technology officer, will continue to serve as interim CEO while the Sourcefire board conducts a search for Burris' successor. --Written by James Rogers in New York. Follow @jamesjrogers >To submit a news tip, send an email to: email@example.com.