The 30-share pack Sensex failed to hold the opening gains on August 20, ending 74 points lower at 37,328, as investors sought more clarity on reports of a corporate tax rate cut and the widely anticipated fiscal stimulus measures.   The NSE Nifty ended with a loss of 37 points at 11,017.   While the mood of the market looks fragile, investors are pinning hopes on any stimulus or measures from the government to lift the sentiments.   Yes Bank ended the day as the top loser in Sensex, followed by IndusInd Bank, ITC, Axis Bank and ICICI Bank.   On the other hand, Maruti Suzuki, Tata Motors, Infosys, HCL Tech and Mahindra & Mahindra bucked the trend to settle as the top gainers in the Sensex kitty.   IT, auto and technology packs on BSE logged gains of over 1 percent, whereas indices of metals, realty, energy and basic materials declined over 1 percent.