BENGALURU, April 21 (Reuters) - Indian shares opened marginally higher on Friday as investors were cautious after a weak revenue outlook from HCLTech Ltd and ahead of the quarterly earnings of the country's top firm by market capitalisation, Reliance Industries Ltd.

The Nifty 50 was up 0.06% to 17,634.55, as of 9:40 a.m. IST, while the S&P BSE Sensex gained 0.08%.

Nine of the 13 major sectoral indexes advanced. Information technology (IT) firm HCLTech rose as much as 3.52% after reporting a rise in consolidated net profit for the March quarter on Thursday.

But caution over the IT sector prevailed as the company forecast lower-than-expected revenue growth for FY2024 on spending cuts and project ramp-downs.

IT stocks, which are up 0.5%, have led the recent slide in the markets, following the weak earnings reports from Tata Consultancy Services Ltd and Infosys Ltd.

The benchmark Nifty 50 is down over 1% so far this week, while the heavyweight IT has lost 6%.

Investors also awaited Reliance's quarterly results, due post market hours on Friday.

Among individual stocks, Cyient Ltd surged over 9% after reporting a 48% rise in revenue in the March quarter on a strong deal pipeline.

Sterling and Wilson Renewable Energy Ltd lost as much as 7.11% after reporting a widened consolidated net loss in the fourth quarter.

($1 = 82.2400 Indian rupees) (Reporting by Bharath Rajeswaran in Bengaluru; editing by Eileen Soreng and Janane Venkatraman)