The key benchmark index Sensex had opened at 17,225 and Nifty at 5,222 level at 9.15 am. Both witnessed a sharp fall after the S&P news hit the market around 12 pm. The Sensex touched an intra-day low of 17,019 and the Nifty fell to 5,163 between 12.05 pm and 12.10 pm. Both recovered after the knee-jerk reaction as European markets opened on a strong note. The Sensex closed at 17,151 and Nifty at 5,222 on Wednesday.