Sirius XM (SIRI) shares rallied 7.9% in the last trading session to close at $26.90. This move can be attributable to notable volume with a higher number of shares being traded than in a typical session. This compares to the stock's 1.7% gain over the past four weeks.SiriusXM shares rallied Monday after Warren Buffett’s Berkshire Hathaway raised its stake in the satellite radio company. Berkshire Hathaway purchased roughly 3.6 million shares for about $87 million in separate transactions, now owning 32% of ...