Why can't I convert my index option buy position from MIS to NRML?
Rejection: Position conversion from MIS to NRML is not allowed for [index] option buy positions.
Zerodha also restricts buying OTM (Out of the money) index options beyond a certain strike price due to the same OI restrictions, see Why am I not able to place Bank Nifty, Nifty option orders for certain strike prices? You can check the allowed strikes for index options using the margin calculator, see Margin calculator.
While this restriction applies to NRML orders, you can trade options intraday using MIS orders for all strikes. This restriction of converting the position from MIS to NRML does not apply to short option positions.
You will only be able to convert your MIS index option buy positions to NRML,
- On expiry day or
- If you have an equal quantity of short position since Zerodha allows buying option contracts as long as they are part of an options strategy.