Being a mere mortal, I am failing to understand what the price of the derivative would be when its underlying basis closed at a constant value in CM until it re-opens.......
How all over the world derivative market is moving when underline cash is closed? It simply demands supply which moves the price whether it is cash or F&O. Underline is not moving F&O.
If there is no liquidity u will see the awkward price on many options contracts. Similarly, liquidity(demand-supply) on a particular future contract affects the price mainly.
Every option trader know sometimes options start moving on their own due to demand-supply only, F&O actually don't care the underline much during the intraday move. That's why in big volatility premium discount varies widely.
And 15 min pre-opening is there to take care of all this difference between Future and spot.
If you follow the F&O market closely on expiry day, specially different option strikes,
then u will easily understand F&O does not care about underline much.
Every F&O contract behaves separately according to demand-supply. And spot price closing is adjusted according to how future expired. Every day future contract doesn't care the spot, the difference is shown by premium and discount which completely depends on demand supply only.
Think it deeply you will get the answer, how Dow future is moving 24-7 when the underline cash is closed? How is SGX nifty moving nicely currently? Moving on its own due to demand-supply only.