Zerodha SL-M order stop loss market BSE NSE freak trade Kite error messages

SL-M orders blocked on BSE (and discontinued for NSE F&O)

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SL-M (stop-loss market) orders are blocked on BSE because the exchange discontinued them across its equity, equity derivatives, currency derivatives and commodity segments to safeguard against erroneous orders and to stop orders executing far from the current market price. On the NSE side, the SL-M order type was withdrawn for index options from 27 September 2021 and is not allowed for index and stock option contracts. Both moves target the same hazard: a market order firing into a thin book and filling at a price far from the trigger, a freak trade. Zerodha blocks the order at Kite to match the exchange rule.

This page covers what the block is, the precise scope on each exchange, why the exchanges withdrew SL-M, and the SL-L substitute that gives you market-like execution certainty while capping the worst fill. The substitute is the practical answer, since for almost every case where you reached for SL-M, a correctly set SL-L does the job with less freak-trade risk.

Conflict-of-interest disclosure. This guide is published by the WebNotes Editorial Team for informational purposes and is written independently. WebNotes operates a Zerodha account-opening referral programme, disclosed on the pages that carry the referral link; this guide does not carry it and earns no referral commission from the procedure described here.

What the block is and which segments it covers

An SL-M order carries a single trigger price and, on triggering, submits a market order for immediate execution at the best available price. BSE has discontinued this order type. The block is segment-wide on that exchange: it applies to equity, equity derivatives (BFO), currency derivatives (BCD), and commodity derivatives. Zerodha states the reason directly: the change was made “to safeguard against the placement of erroneous orders and to prevent orders from being executed far away from the current market price.” So any SL-M routed to a BSE-listed instrument is blocked before it reaches the exchange.

The NSE scope is narrower but predates BSE’s. NSE stopped the facility of stop-loss market orders for index options from 27 September 2021, and SL-M is not allowed for index and stock option contracts on NSE. Zerodha blocked SL-M for index options at that time to reduce freak-trade exposure. NSE equity cash still supports SL-M, so the order type is not gone everywhere; it survives in the NSE cash segment and is absent on BSE entirely and on NSE options.

Why the exchanges withdrew SL-M

The withdrawal targets freak trades. A freak trade is an execution at a price far from the prevailing market, and it happens when a market order arrives into a shallow order book, so the order sweeps through thin price levels and fills at a price well away from where the stock or contract is trading. An SL-M order is built to fire a market order the instant its trigger is hit, which is exactly the condition, often a fast move, where market depth is thinnest. The result is that a stop meant to cap a loss can execute at a price far worse than the trader expected, turning a controlled exit into an outsized one.

Zerodha’s founder, Nithin Kamath, has noted that most brokerages around the world do not support SL-M, or market orders, for options, because of the high volatility and the resulting impact-cost risk. The exchanges’ withdrawal of SL-M in options and BSE’s segment-wide block apply that logic at the venue level: remove the order type that most reliably produces freak fills, rather than rely on each trader to avoid it. This sits alongside the execution range and price-band controls that bound how far a trade can print from a reference price.

The SL-L substitute, configured to act like SL-M

The replacement is an SL-L (stop-loss limit) order set up to behave like a market order on triggering while still capping the worst price. An SL-L carries two prices: a trigger price that releases the order, and a limit price that bounds the execution. The technique is to place the limit well past the trigger in the direction of the exit, so the order fills against everything between trigger and limit, like a market order, but refuses to fill worse than the limit, unlike one.

For a sell stop protecting a long position, set the trigger at your stop level and the limit a little below it. Zerodha’s worked example: a sell SL order with a trigger of Rs 95 and a limit of Rs 94.90 sends a sell limit order to the exchange when Rs 95 is reached, filling down to Rs 94.90. Widen that buffer for a volatile or illiquid contract so normal fills still go through. For a buy stop protecting a short, the trigger sits above the market and the limit a little above the trigger. The trigger-versus-limit-price mechanics are the same as any SL order; the only design choice is how wide to set the buffer.

The trade-off you accept

The SL-L substitute is not a free swap. If the market gaps straight through your limit when the trigger fires, the order rests unexecuted at the limit price, so your stop may not fill at all and the loss runs further than the stop intended. A true market order would have filled at whatever price the book offered, however bad; the SL-L trades that certainty of execution for certainty of price. The choice is therefore between two failure modes: SL-M risks a freak fill far from the trigger, and SL-L risks no fill in a gap. The exchanges decided the freak-fill risk was the worse of the two for market integrity, which is why SL-M is the order type they withdrew. For a liquid instrument, a modest buffer makes a non-fill unlikely while still ruling out a freak print; for an illiquid one, neither order type is safe, and the better answer is often not to trade a market-style stop there at all.

Where SL-M still works and where it does not

To summarise the scope: SL-M is blocked across all BSE segments, blocked on NSE index and stock options, and still available in the NSE equity cash segment. If you need a stop on a BSE instrument or an NSE option, use the SL-L configuration above. If you are on NSE cash and prefer the execution guarantee, SL-M remains available there, with the freak-fill caveat. Read how to place an SL-M order on Kite for the order-entry steps where SL-M is permitted, and SL-M with trigger outside circuit limits for the related case where a trigger sits beyond the day’s price band .

See also

External references

References

  1. Zerodha support, Why are Stoploss Market (SL-M) orders blocked on BSE? (segment-wide discontinuation across equity, BFO, BCD and commodity; as of 21 June 2026).
  2. Zerodha market intel, Stop-loss market (SL-M) orders blocked for index options (NSE withdrawal of SL-M for index options from 27 September 2021).
  3. Zerodha support, How to use a Stoploss-limit (SL) order like a Stoploss-Market (SLM) order (SL-L configuration and the Rs 95 trigger, Rs 94.90 limit example).
  4. NSE circular on discontinuation of stop-loss market orders in the options segment, effective 27 September 2021.

Related articles

Frequently asked questions

Why are SL-M orders blocked on BSE?
BSE discontinued stop-loss market orders across its equity, equity derivatives, currency derivatives and commodity segments to safeguard against erroneous orders and to prevent orders executing far from the current market price, which is how freak trades occur.
Are SL-M orders blocked on NSE too?
Partly. NSE stopped SL-M for index options from 27 September 2021 and does not allow SL-M for index and stock option contracts. NSE equity cash still supports SL-M. The blanket block is on BSE, which withdrew SL-M across all its segments.
What is a freak trade?
A freak trade is an execution at a price far from the prevailing market, caused by thin market depth at the moment a market order arrives. A stop-loss market order can fire into a shallow book and fill at a price well away from the trigger, which is the risk the exchanges withdrew SL-M to remove.
What should I use instead of SL-M on BSE?
Use an SL-L (stop-loss limit) order with the limit price set well below the trigger for a sell, or well above for a buy. The order then behaves like a market order on triggering but caps the worst fill price, protecting against a freak trade.
What is the risk of using SL-L as SL-M?
If the market gaps straight through your limit price when the trigger fires, the SL-L order rests unexecuted at the limit, so your stop may not fill and the loss can run further than intended. A true market order would have filled at any price; the limit trades that certainty for price protection.
How far should I set the SL-L limit from the trigger?
Wide enough that normal fills go through but narrow enough to cap a freak fill. A common approach is a small buffer past the trigger, for example a trigger of Rs 95 with a sell limit of Rs 94.90 on a liquid scrip, widened for volatile or illiquid contracts.

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