Ahead of March derivative contract expiry, the benchmark\u00a0BSE Sensex today closed 50 points down to nearly 10-week low of 28,111.83 on losses in capital goods, power and metal stocks, extending its string of losses to the sixth straight session. Sensex constituents such as L&T, SBI, TCS, NTPC, ONGC, GAIL, Coal India, Tata Steel, BHEL and Tata Power suffered losses. ICICI Bank, Tata Motors, Sun Pharma, Wipro, M&M and Sesa Sterlite notched up gains, cushioning the index's drop. Small-cap and mid-cap indices continued their decline on sustained selling by retail investors, underperforming Sensex. Caution prevailed in markets as traders were busy carrying forward their positions to April 2015 series as the March contract is set to expire tomorrow. The BSE 30-share barometer resumed better and improved further to a high of 28,249.60 before falling back to a low of 28,031.42. It finally, closed at 28,111.83 - a loss of 49.89 points or 0.18 per cent. In straight six sessions, the Sensex has plunged by 624.55 points or 2.17 per cent. Previously, it had settled at 28,075.55 on January 15, 2015. The broad-based 50-issue NSE Nifty also moved down further by 12.15 points, or 0.14 per cent, to 8,530.80. "In absence of any major cues, equity benchmarks upheld their prevailing consolidation bias and closed almost unchanged on Wednesday. Adding negativity to dampened sentiments, stocks have been extremely volatility ahead of F&O expiry," said Jayant Manglik, President-retail distribution, Religare Securities.