Mumbai, Sep 17 - A key index of Indian equities markets ended a highly volatile session marginally in the green Thursday.

The 30-scrip sensitive index (Sensex) of the Bombay Stock Exchange (BSE), which opened higher at 16,686.38 points, closed at 16,711.11 points, up 34.07 points or 0.2 percent.

The index that hit a high of 16,820.02 points in the morning session shed most of its gains by noon on profit booking. It slipped to an intra-day low of 16,636.55 points.

The Nifty of the National Stock Exchange (NSE) ended marginally in the red at 4,948.6 points, down 0.2 percent.

Broader market indices ended in the positive terrain, with the BSE midcap index closing 0.27 percent higher and the BSE smallcap index up 0.13 percent.