The Sensex opened 16 points higher at 8612. After touching a high of 8639, the index slipped into the negative zone to touch a low of 8547. Presently the index is down 14 points at 8582. Ranbaxy is the biggest gainer among the Sensex stocks, it is up 3% at Rs400. Bajaj Auto at Rs 1,920 and Reliance Energy at Rs 568, are up 1% each. Whereas, Grasim, HDFC, Infosys and Tata Power are down over 1% each.