A market order is an instruction to buy the specified quantity of a scrip irrespective of the price it is available at. In the case of illiquid contracts, the bid/ask price could be at a price far from the last traded price or the theoretical price of the contracts.

We have had customers placing market orders without checking bids/asks on such contracts and losing money due to trade execution at arbitrary prices. Market orders are hence blocked for illiquid index options and all stock options.

Market and SL-M orders are blocked for all MidcapNifty contracts due to illiquidity.

For FinNifty, Market orders are only allowed for option contracts whose OI is over 500 lots or 20,000 quantities.

You will be able to place market orders for Nifty and Bank Nifty options with adequate liquidity for the below expiries:

1. Current and next week.
2. Current month.

Market orders are blocked for:

1. All weekly expiries other than the current and next week.
2. All monthly expiries other than the current month.
3. Deep ITM contracts (which are more than 5% in the money)

Market order AMOs are blocked for all monthly index options. However, you can place limit orders for any of these contracts at or greater than the best bid/ask price to instantly execute your trade like a market order.