Mumbai: The entire initial gains were diluted on heavy profit-taking by investors amidst extreme volatility on the back of continued global turmoil, coupled with domestic macro worries, leading the benchmark S&P CNX Nifty to end almost flat at the NSE. The 50-share Nifty index swung widely between a high of 5,030.15 and a low of 4,911.05 before closing at 4,940.95, a marginal loss of 5.85 points, or 0.12 percent, over its last close. The bourses rebounded sharply from its overnight fall on positive vibes generated by firm Asian cues amidst hectic short-covering and low-level buying, it continued to gain as trading progressed and managed to hold the important 5,000 mark level. But the key-index faced sudden bouts of selling pressure in mid-afternoon as volatility struck due to weak European opening on escalating euro-zone debt crisis and gave away entire gains to touch the day''s lowest point. It made few failed attempts to recover before ending with marginal losses. "Investors scrambled for hectic profit-booking at higher levels after the two sessions steep fall as deep concerns mounted with the overlapping of global uncertainties with disappointing domestic growth outlook as well as rate hike fears later this week," traders said. Tata Motors, SBIN, Sun Pharma, Cipla, Tata Power, Bharati Airtel, HDFC, ONGC, L&T, Hindunilever were the top losers from the Nifty. However, Cairn, Sesa Goa, Kotak Bank, ACC, DLF, Bajaj Auto, Reliance Capital, Jindal Steel, Seimens and Rcom ended with gains. Turnover in cash segment moved down to 9,832.73 crore from 9,893.50 crore yesterday. A total of 6,282.52 lakh shares changed hands in 53,77,333 trades. The market capitalization stood at 58,89,823 crore.