Indian equities were trading flat as the markets opened on Wednesday after two key indices had ended marginally lower the day before, tracking the US counterparts that had closed in the red.The sensitive index (Sensex) of the Bombay Stock Exchange (BSE) opened at 27,473.36 points, against the previous close at 27,440.14 points. Some 10 minutes into trading, the key index was down 62.55 points, or 0.23 percent, at 27,377.59 points.The Sensex had closed Tuesday down 50.45 points, or 0.18 percent, amid volatile trading.At the National Stock Exchange, the Nifty was down 21.70 points, or 0.26 percent.