Many factors. One, there is a change in the global  investment climate. One of the primary triggers is the huge fear of the  United States' economy going into a recession with foreign  institutional investors trying to reallocate their funds from risky  emerging markets to stable developed markets. Analysts are now expecting  a cut in US interest rates. Hedge funds and FIIs could have been  the biggest sellers in the Indian markets, booking profits and making  the most of the unprecedented bull run that has dominated the Indian  stock market for a long time now. 
The current volatility is also linked  to global bourses. There is a big correlation among global markets. The  presence of hedge funds across asset classes, along with increased  global movement of capital, has increased event-related volatility. Volatility in commodities markets has also significantly affected equity markets. A combination of global and local  factors is affecting this market, said Mihir Vora of HSBC Mutual Fund,  on NDTV Profit. On the global front, other emerging markets were down  nearly 20% so India is playing catch-up, he said. 
On the local front there has been a  huge build-up in derivatives positions and volatility led to margin  calls. Also many IPOs have sucked out liquidity from the primary market  into the secondary market, said Vora. At current levels it would be a  buy call and we would not advise investors to wait to catch the bottom,  he added. 
