The Sensex gained nearly 127 points in opening trade today as investors targeted fundamentally strong stocks available at attractive prices. The 30-share BSE index rose by 127 points to 18,135 points in early trade after shedding 441 points in the previous session on Friday. Similarly, broad-based National Stock Exchange Nifty index also moved up by 36 points to 5,432 points. Brokers said the investor sentiment was boosted by fresh buying on the back of firming global trend. In particular, IT and refinery sectors available at attractive lower levels garnered a lot of investor interest.