* NSE index down 0.21 pct, BSE index 0.12 pct lower
* Both indexes head for third straight weekly gain
* Axis Bank, Reliance Industries among top gainers
By Shivam Srivastava
Jan 13 (Reuters) - Indian shares edged down on Friday as market heavyweight Tata Consultancy Services Ltd slumped on worries about its future following key management changes.
Shares of the IT outsourcing giant fell about 4 percent to a one-month low as CEO Natarajan Chandrasekaran's departure to head holding company Tata Sons as chairman overshadowed the company's better-than-expected December-quarter results.
Adding to the fall, Infosys shares declined on profit-taking after the company posted positive quarterly results, but narrowed its full-year revenue guidance range.
Infosys fell as much as 3.73 percent to its lowest since Dec. 7, coming off a two-and-a-half-month high touched earlier in the session.
Earlier in the day, the country's second biggest software services company posted a better-than-expected 7 percent rise in third-quarter profit.
"Market was overheated ahead of Tata Consultancy Services and Infosys Ltd reporting their results," said RK Gupta, managing director, Taurus Asset Management Company
"We can also see a bit of profit-booking as well as caution ahead of Donald Trump taking over the U.S. presidency."
The broader NSE index was down 0.21 percent at 8,389.20 as of 0744 GMT, while the benchmark BSE index was 0.12 percent lower at 27,214.51.
Both indexes were still headed for a third straight weekly gain, with the NSE index up 1.98 percent and the BSE 1.82 percent higher. Both hit their highest levels in around two months on Wednesday.
IT shares led losses with the Nifty IT index down 1.01 percent. The sub-index has been flat this year on fears of tougher U.S. visa rules after Donald Trump becomes the president on Jan. 20.
Banks extended their rally as they are flushed with deposits after India late last year banned higher-value banknotes. The Nifty Bank index has rallied 3.83 percent so far in 2017.
Axis Bank was up 2.6 percent, while HDFC Bank Ltd rose 2.1 percent.
Energy stocks rose as crude oil edged up, supported by reports on details about OPEC output cuts.
Reliance Industries Ltd was up 1.01 percent ahead of its quarterly results on Monday, while Oil and Natural Gas Corp was 1.68 percent higher. (Reporting by Shivam Srivastava in Bengaluru; Editing by Subhranshu Sahu)