The benchmark Bombay Stock Exchange (BSE) index, Sensex, gained 893.73 points (6.20%), its biggest weekly gain in absolute terms, to close at 15,318.60 during the week ended August 31 over the last weekend close of 14,424.87.The bullish trend is expected to gather momentum on the back of the 9.3% GDP growth in the April-June quarter and inflation dropping below the 4% mark.The stock markets logged huge gains during the week on the back of hectic short-covering prompted by encouraging global developments, which indicated a possible rate cut by the US Federal Reserve.Foreign institutional investors (FIIs), which had been heavy sellers during the entire month, began covering short positions and reported net purchases of Rs 1,258 crore in the week.Domestic institutional investors (DIIs) played an important role in the unprecedented weekly rally by investing Rs 1,390 crore.Indications of domestic political stability also boosted market sentiment.