The Sensex gained 37 points in early trade. The 30-share index rose further by 37.08 points to 17,468.92. It has gained over 568 points in the past three sessions. In a similar fashion, the wide-based National Stock Exchange Nifty index gained 9.45 points at 5,279.35. Brokers said continued buying by FIIs on the Indian bourses and encouraging quarterly earnings by some corporate mainly buoyed the trading sentiment but a weak trend on other Asian bourses, capped the gains.