Mumbai: The SENSEX opened firm and later showed irregular movements during morning trading on the Bombay Stock Exchange (BSE) on July 7 on alternate bouts of buying and selling by operators and foreign funds.

The BSE sensitive index opened remarkably up at 3,631.46 as against July 4 close of 3,622.34, but later fluctuated erratically in a range between 3,645.42 and 3,626.34 before being quoted at 3,628.11 at 10.30 am (IST).

Driven by speculators, the market remained bullish with several index-based counters continuously in demand, brokers said, adding that the principal driving force behind the market was the consistent net investments by Foreign Institutional Investors (FIIs), which made net purchases of Rs 663 crore in the first four sessions last week, taking the total net investments to Rs 6,710 crore in the current year.

Heavyweights like Bajaj Auto, BSES, BHEL, Cipla, Glaxo, Grasim, HPCL, Ranbaxy Lab, SBI and Telco were quoted higher on fresh buying support.

However, Infosys Tech, Satyam Computers, HCL Tech, L&T and a few others showed moderate falls.

PTI