BUZZ-Rolls Royce: extends gains on ValueAct stake buy
** Engineering firm's shares up 4 pct as they continues to gain from Friday's announcement that U.S. activist investor took a 5.44 pct stake in the co
** Stock poised for biggest two-day gain since 2011 following Friday's 6 pct rise
** ValueAct now largest shareholder in co
** Co's shares second-largest gainer on bluechip FTSE 100 , with a third of its daily avg volume going through in the first 40 minutes of trade
(venkateshasoumithri.mamidipudi.thomsonreuters.com@reuters.net)