The Sensex opened firm over its yesterday's close at 6,636 - up 16 points. Buying from steady to modest gains in old and new economy stocks has pushed the index to an early high of 6,653. It is now up 32 points at 6,652. The Nifty, too, has opened firm with a surge of 20 points at 2,099.Reliance is up Rs 2 at Rs 543. ITC is up a per cent (Rs 10) at Rs 1,339, and HLL is up 1.57% (Rs 3) at Rs 168.SBI has advanced 1.52% (Rs 10) to Rs 666. While ICICI Bank is up a per cent (Rs 4) at Rs 373, HDFC Bank is up Rs 3 at Rs 575.Infosys (up Rs 5 to Rs 2,108), Wipro (up Rs 8 to Rs 702) and Satyam (up Rs 2 to Rs 410) have logged decent gains in early trades.ONCG is up with a steady gain of Rs 3 at Rs 836. HDFC has gained 2.17% (Rs 17) to Rs 788.ACC is up 1.13% (Rs 4) at Rs 367. Other cement majors have also resumed in the green.Ranbaxy, Dr. Reddy's and Cipla have clocked a per cent gain each to Rs 1,066, Rs 718 and Rs 286, respectively.