Weekly stocks review: A host of positive factors kept the mood in the stock market upbeat for the fourth straight week with the biggest weekly gaining streak since September 2010,sending the benchmark Sensex up by another 495 points to end over 11-week high of 17,233.98. Sensex gained 1,779.60 points or 11.51 per cent in the straight fourth week as also in the current month,between January 2 to January 27,2012. Buying was seen across-the-field as barring realty,other 12 sectoral indices closed with sharp to moderate gains between 5.64 per cent and 0.71 per cent,while 20 out of 30 Sensex-based scrips registered increase in their values. The first day of the week saw some lacklustre activity but on the second day investors' confidence surged after the Reserve Bank of India in its third quarter monetary policy review cut the cash reserve ratio (CRR) by 50 basis points to infuse liquidity in the system,keeping the short-term lending rate unchanged. The move will pump Rs 32,000 crore into the financial system,and gives signals of a cut in the lending rate in the near future. One of the main reasons behind the current gush was also the frantic buying by Foreign Institutional Investors (FIIs),the main market movers,who injected Rs 3,308.66 crore in the week (including provisional data of January 27) and Rs 9,073.10 crore in the current month till January 25 as per Sebi figures.