* NSE index down 0.03 pct, BSE index 0.21 pct higher
* Asian shares fall after Yellen comments
* Bank shares gain; ICICI Bank up 7 pct
Oct 17 - Indian shares swung between gains and losses on Monday as investors braced themselves for a tepid quarterly earnings season, with global equity markets trading lower after Federal Reserve Chair Janet Yellen's comments on the U.S. economy.
Yellen, in a speech at a conference of policymakers and academics, laid out the deepening concern at the Fed that U.S. economic potential is slipping - and may need aggressive steps to rebuild.
Markets back home were a bit groggy after September-quarter results of Tata Consultancy Services and Infosys - two of India's biggest software exporters - failed to cheer investors.
"Earnings will definitely remain a key trigger for the markets and investors are allocating funds depending on how the earnings will pan out," said Deven Choksey, managing director at KR Choksey Securities.
This week, companies such as Biocon, Reliance Industries, ACC, Wipro and HCL Technologies are slated to report quarterly results.
The benchmark BSE index was 0.21 percent higher at 27,728.54 as of 0546 GMT, after easing marginally earlier in the day.
The broader NSE index was down 0.03 percent at 8,581.20 after gaining as much as 0.37 percent earlier in the session.
Among the gainers, three of the biggest lenders to the Essar Group rose after the debt-laden company agreed to sell an oil unit to a consortium led by Russia's Rosneft. Shares of ICICI Bank jumped 7 percent, Axis Bank rose 1.7 percent while State Bank of India was up 1.1 percent.
State-run oil refiners such as Bharat Petroleum Corp and Hindustan Petroleum Corp rose more than 1 percent each on a hike in petrol prices.
However, NIIT Technologies declined 3.9 percent after the IT firm on Saturday said its September-quarter profit dropped about 9 percent.
Network18 Media & Investments shed 1.4 percent after its September-quarter consolidated loss widened.
Reporting by Aastha Agnihotri in Bengaluru; Editing by Sunil Nair