The exchanges set a MWPL (Market-wide positions limits) for all stocks traded in the F&O segment, which is the maximum number of contracts that can be open at any given time (Open Interest). If the open interest of any stock exceeds 95 percent of the MWPL (all futures and options contracts of that stock), all F&O contracts of that stock enter a ban period.

When a stock's futures and options contracts are in the ban period, no new positions are allowed in any of the stock's futures and options contracts. During this time, you will only be able to exit existing positions. Only if the open interest falls below 80% is the ban lifted.