New Delhi, March 11: The BSE benchmark Sensex soared 383 points to reclaim the 37,000 mark Monday, posting its biggest gain in nearly six months, led by gains in RIL, ICICI Bank and Bharti Airtel amid sustained foreign fund inflow and positive global cues.According to experts, investors widened their portfolios amid hopes of a win for the incumbent NDA government, following the announcement of 2019 general election dates Sunday.The 30-share Sensex started off on a strong footing and reclaimed the 37,000 mark on widespread buying by investors, and ended at 37,054.10, up by 382.67 points, or 1.04 per cent.This is the highest closing level since September 19 last year when it had closed at 37,121.22. The gauge had settled 53.99 points, or 0.15 per cent, lower at 36,671.43 on Friday.The NSE Nifty, after climbing to 11,172.40 - its highest since September 26 last year - closed at 11,168.05 points, up 132.65 points, or 1.20 per cent. Power, oil and gas, PSU, metal, banking, auto, capital goods, infrastructure and healthcare sector stocks witnessed heavy buying through the session.Experts see this as a pre-poll rally following the announcement of 2019 general election dates. Prevailing geopolitical concerns in the wake of recent India-Pakistan military conflicts will be a key factor in the upcoming general elections that may help incumbent NDA government at the centre, they said.Lok Sabha elections will begin on April 11 and will be held over seven phases followed by counting of votes on May 23, the Election Commission announced on Sunday. In afternoon trade, the rupee appreciated 21 paise to 69.93 against the dollar.