Why am I not able to place market orders for some index and all stock option contracts at Tiqs?

A market order is an instruction to buy a specified quantity of a security at whatever price is available in the market. In the case of illiquid contracts, the bid/ask price may be far from the last traded price or the theoretical price of the contract. As a result, if you place a market order for an illiquid contract, you may end up paying an arbitrary price that could be much higher or lower than the actual value of the contract. Market orders for illiquid index options and all stock options are thus blocked.

Due to illiquidity, all Mid cap Nifty contracts have market and SL-M orders are blocked. And market orders for Fin Nifty are only permitted for the current weekly expiry for At-The-Money (ATM) option contracts i.e., up to 1% of ITM/OTM. You will be able to place market orders for Nifty and Bank Nifty options with sufficient liquidity for the expirations listed below:

• This week and the following week.
• The current month.

Market orders are halted for the following reasons:

• All weekly expirations other than the current and following weeks.
• All monthly expirations except the current month. Market order AMOs for deep ITM contracts (more than 5% in the money) are prohibited for all monthly index options.

However, you can place limit orders for any of these contracts at or above the best bid/ask price to execute your trade as quickly as a market order.