Market-Wide Position Limit (MWPL)
A SEBI-mandated ceiling on the total open interest across all market participants in the futures and options contracts of a single stock, set at 20 percent of the free-float shares outstanding, beyond which the stock enters an F&O trading ban.
The Market-Wide Position Limit, universally abbreviated as MWPL, was introduced by SEBI as a systemic risk control for single-stock derivatives. The rule stipulated that the aggregate open interest across all exchanges in futures and options on any individual stock could not exceed 20 percent of the number of free-float shares outstanding of that company. NSE published MWPL figures for every F&O-eligible stock on its website, and these figures were updated whenever corporate actions such as stock splits, bonus issues, or changes in promoter shareholding altered the free-float count.
The ban mechanism worked in two stages. When aggregate open interest in a stock crossed 95 percent of its MWPL, NSE placed the stock in an F&O ban period. During this ban, no new positions — whether fresh long futures, short futures, or new option contracts — were permitted. Existing positions could be continued or reduced, but not increased. The ban was lifted only after open interest declined below 80 percent of the MWPL, at which point fresh positions could again be initiated.
SEBI justified this limit on the grounds that excessively large derivative positions relative to the underlying free float could distort price discovery in the cash market, allow concentrated entities to wield outsized influence over settlement prices, and create artificial demand or supply signals. The 20 percent threshold was arrived at through empirical study of liquidity and float characteristics of Indian listed companies.
For traders, the MWPL ban created a practical constraint. Positions initiated before a ban could not be augmented. Participants who wanted to increase their hedge ratio or scale a winning position found themselves unable to do so during the ban period. The ban also affected arbitrageurs who relied on the ability to add fresh legs to spread strategies.
Index futures and options were not subject to MWPL restrictions, as they represented baskets of stocks rather than individual names. The limit was specific to single-stock futures and options — the contracts colloquially referred to as stock F&O as distinct from index F&O.