The Sensex is exhitbitig high volatility. From a high of 13,723 in the opening trades, the index tumbled to a low of 13,534.The index is swinging in and out of the positive zone and is now down 25 points at 13,607.Garsim and Gujarat Ambuja have surged 2.5% each to Rs 2,329 and Rs 126, respectively. ACC has gained 1.7% at Rs 931.ITC has rallied 2.3% to Rs 170. Tata Steel, Dr.Reddy's, SBI and Satyam have moved up around 1.7% each to Rs 467, Rs 694, Rs 1,076 and Rs 456, respectively.Ranbaxy has shed 2.4% to Rs 348. Reliance Communications has tumbled nearly 2% to Rs 424.