Mumbai, Aug 11 - A key index of the Indian equities markets opened in the red Tuesday, and slipped further soon after to be 73 points in the red about five minutes into trade.

The weak start was primarily due to other key Asian indices which were trading almost flat.

The sensitive index (Sensex) of the Bombay Stock Exchange (BSE) opened at 15,000.38 points, as against Monday's close at 15,009.77 points. It soon slipped to 14,936.56 points, 73.21 or 0.49 percent down from its previous close.

The broader S&P CNX Nifty of the National Stock Exchange (NSE) too was trading in the negative terrain and was at 4,418.05 points, a fall of 0.44 percent.

Broader market indices were trading flat with the BSE midcap index up 0.01 percent, while the BSE smallcap index was ruling 0.02 percent higher.