**A Random sample of my thoughts
**
If Nifty falls / Nifty rises , does the implied vol move in the same direction of the underlying or does it move the opposite direction. This becomes a very important question in the context of choosing a local volatility idea or chucking such an idea ? Local vol models assume that underlying and smiles move in different directions!! As there is a short sale restriction on stocks, what exactly is a tradable underlying for Nifty option, for valuation purposes ?