The Bombay Stock Exchange benchmark Sensex gained 524 points and regained the 13,000 level in early trade on Thursday on fresh buying by funds as well as investors, tracking the global markets.
Breaking the four-session losing streak, the 30-share index, which had lost nearly 1,350 points, climbed 523.81 points to 13,099.61 on the back of a significant rise in heavy-weight stocks.
Covering-up of short positions by speculators also influenced the trading sentiments to some extent, marketmen said.
Similarly, on the wide-based National Stock Exchange's index Nifty gained 152.05 points to 3,968.75.
Stock brokers said firming global stock markets mainly influenced the trading sentiments here, triggering all-round buying.
The Hong Kong's Hang Seng index rose nearly 2.66 per cent in early trade.
Major supporters to the Sensex were stocks such as Reliance Industries, Rcom, Reliance Infra, DLF Ltd, ONGC, Maruti Udyog, Tata Motors, Tata Steel, ACC, Ranbaxy, State Bank of India, BHEL, Larsen and Toubro, Infosys Technologies, TCS, Wipro and Satyam Computers.