Niva Bupa Health Insurance Company could not enthuse investors on its debut day as shares closed flat, following weak conditions in the equity markets on November 14. The Nifty 50 has shed 10.4 percent from its record high of September 27. The stock opened higher at Rs 78.14 on the NSE, up 5.6 percent over the issue price and hit an intraday high of Rs 81 in early trade.