Its very important for traders to understand that FII's almost always trigger a medium term trend reversal.
Look at the statistics over
here
In January 2008, they were the first to sell which triggered the biggest bear market in a decade.(while the DII's foolishly continued to buy)
In April & May 2009, they were the first to buy which triggered a massive bull run (while the DII's were actually net sellers)
In Dec 2010, Jan 2011 and Fed 2011 they were massive sellers triggering an intermediate term downtrend (as usual DII's were stupidly buying)
In Jan and Feb 2012, they were huge buyers again triggering a minor uptrend. (while DII's were as usual silly and selling)
But there is another deeper point here for anyone observing with some intellect. If the FII and DII bought simultaneously the markets would basically hit the upper circuit as we are not liquid enough to absorb such buying similarly,
If the FII and DII sold simultaneously we would continuously hit the lower circuit as we our markets are not liquid enough to absorb such selling.
The client and proprietary traders in India are not big enough to counteract the combined buying/selling of the FII's and DII's.
Once you understand this, its not difficult to understand why the FII and DII always take opposing positions and try to balance our markets to the state it is in currently.
All that said, Currently FII's are net sellers to neutral in the Indian markets. Without their participation, its impossible to be in an intermediate term uptrend.