BENGALURU, Dec 31 (Reuters) - Indian shares were set to log their highest annual gains since 2017 as they traded sideways on Thursday in their last 2020 session, with the benchmark Nifty index set to finish the year 15% higher. The NSE Nifty 50 index was up 0.06% at 13,991.95 by 0444 GMT, while the S&P BSE Sensex was 0.07% higher at 47,784.31. The Nifty rose for a seventh straight session, briefly hitting a life-time high of 13,997.85. “Foreign inflows are very dull today as it’s the year end but the undercurrent is very strong and the Nifty could cross the 14,000 level,” said Rusmik Oza, head of fundamental research at Kotak Securities in Mumbai. The Nifty has gained 14.9% so far this year and the Sensex has added 15.74%. Both indexes have hit record highs and are set for their best year since 2017 after plunging to multi-year lows in March as the COVID-19 pandemic hit Asia’s third largest economy. News on vaccine development and measures from global central banks to cushion the economic fallout from the crisis have helped the indexes log annual gains. The Nifty IT index has rallied more than 55% so far in 2020 and was on track for its best year since 2013. It was down 0.53% for the day. The Nifty Phrama index, which has been the best performer among the main sub-indexes, gaining 59% so far in 2020, was up 1.27%. Reliance Industries Ltd, India’s most valuable company, rose 0.6% and was among the top three boosts to the Nifty. Meanwhile, U.S. stocks finished higher overnight and Asian shares hovered near record highs on Thursday as investors bet on a speedy economic recovery in 2021 amid COVID-19 vaccine rollouts.