Most discussion of risk in Indian investing is about price falling. There is a second risk that gets almost no attention and is worse when it arrives: the price falls and there is nobody to sell to.
India has an explicit set of mechanisms that produce exactly that situation, and they are worth understanding before you need them rather than during.
What a circuit limit is
Every listed share has a price band — a maximum percentage it is permitted to move from the previous close in a single session. Commonly five, ten or twenty percent, assigned by the exchange according to the characteristics of the share.
Reach the top of that band and the share is at its upper circuit. Reach the bottom and it is at the lower circuit. Trading does not stop; what stops is movement beyond the band, and orders can still be placed inside it.
The purpose is straightforward and reasonable. It prevents a single session of panic or frenzy from moving a price to a level nobody would defend the next morning, and it gives participants a night to think.
What people misunderstand is what happens at the boundary. A share at its lower circuit is not simply down twenty percent. In most cases it means everybody who wants to sell is queued at that price and there are no buyers. Your sell order joins a queue that is not moving. You have not lost twenty percent — you have lost twenty percent and cannot act on it.
Note that the index has its own separate mechanism. Large moves in the broad market trigger a market-wide halt for a defined period, and in an extreme case for the rest of the session. That is a different instrument from a single share's band and applies to everyone at once.
Locked circuits, and the days that follow
The uncomfortable part is not day one. It is what a circuit can do across several sessions.
When bad news arrives on a share that few people trade, the price can hit the lower circuit at the opening bell and stay there. The next morning it opens lower and does the same. This can continue for several sessions, and the whole way down there is no meaningful opportunity to exit — each day's decline happens without a functioning market in between.
Which produces the most important practical conclusion in this article: a stop-loss does not protect you here. A stop-loss is an instruction to sell when a price is reached, and it depends on somebody being willing to buy at that price. In a locked circuit there is nobody, so the order sits unexecuted while the price continues away from you on subsequent days. People who believe their downside is capped by a stop discover this in exactly the situation where it matters.
The exposure is concentrated in a specific place, and it is worth naming plainly. This almost never happens in large, heavily traded companies, where there are buyers at some price on any given day. It happens in small and thinly traded ones, and the tighter five percent bands are typically applied to precisely those. So the risk of not being able to exit sits alongside every other risk of small companies rather than being independent of it.
ASM and GSM: when the rules change on a share
Separately from price bands, the exchanges operate surveillance frameworks that apply additional restrictions to individual shares. The two commonly encountered are the Additional Surveillance Measure and the Graded Surveillance Measure.
A share can be placed under these for reasons connected to how it is trading rather than to anything the company has announced — unusual price movement, unusual volume, concentration among a few participants, or valuations far outside any comparable. It is a monitoring mechanism, not a verdict, and inclusion does not itself mean wrongdoing has occurred.
What changes for you as a holder can be substantial:
Margin requirements rise sharply, in some stages to a very high percentage of the trade value, which effectively removes any leverage and makes positions much more expensive to hold.
Settlement can move to trade-for-trade, meaning every transaction must be settled by delivery and intraday buying and selling in that share is no longer possible.
In the stricter stages, continuous trading can be replaced by periodic call auctions — the share trades only at intervals during the session rather than continuously, which is a dramatic reduction in the ability to transact.
The stages escalate and de-escalate on published criteria, and the frameworks are revised periodically, so the current rules should be read from the exchange's own documents rather than from any article. What matters here is the shape of it: the rules governing a share you already own can tighten without the company doing anything at all, and the tightening always reduces your ability to get out rather than in.
What to do with this
Three practical consequences, in order of how much they matter.
Check liquidity before you check anything else. Not the volume on an exciting day — the ordinary daily volume across a dull month, and the size of the gap between buy and sell prices. If a normal day's turnover is small relative to what you intend to hold, your exit is theoretical.
Treat a stop-loss as a tool for ordinary conditions. It works well in liquid shares in normal markets, which is most of the time. It does not work in the situation it is most often imagined to protect against, and believing otherwise leads directly to oversized positions in illiquid companies.
Look up the surveillance status before buying something unfamiliar. Both exchanges publish the current lists. It takes a minute, and a share already under additional measures is telling you something about the last few months that a price chart alone will not.
None of this argues against small companies as investments. It argues that the position size has to account for the exit, not just the entry — and that a holding you cannot leave is a different risk from a holding that has fallen.
An account that shows the limits
Price bands and surveillance flags appear on the order screen. Free to open
Price band rules, surveillance criteria and the stages within each framework are set by the exchanges and SEBI and are revised from time to time — read the current documents rather than relying on this description. This is educational material, not advice, and nothing here is a recommendation about any share. We run no tips group and no signal service, we manage nobody's money, and no return is promised.
Disclosure: the account-opening link on this page is under Atul Shrivastava's Zerodha Authorised Person registration (NSE AP Reg: AP2516003481; Zerodha Broking Ltd. SEBI Reg: INZ000031633) and earns a revenue share. TheFinBaba is not a SEBI-registered Investment Adviser — this content is educational, not investment advice.
Frequently Asked Questions
What does it mean when a stock hits the lower circuit?
It has fallen to the bottom of its permitted band for the session and cannot go lower that day. In practice it usually means sellers are queued with no buyers, so the more useful reading is that you cannot exit rather than that the price has stopped falling.
Will my stop-loss protect me in a circuit?
No. A stop-loss becomes an order to sell, and an order needs a buyer. In a locked circuit there are none, so it stays unexecuted while the share continues lower on following sessions. It is a tool for ordinary liquid conditions, not for this one.
What is the difference between ASM and GSM?
Both are exchange surveillance frameworks that apply extra restrictions to individual shares, with graded stages. They differ in criteria and in the measures applied, and both can raise margin requirements sharply, force delivery-based settlement, or restrict a share to periodic auctions instead of continuous trading.
Does a stock under surveillance mean the company has done something wrong?
Not necessarily. Inclusion is usually triggered by how the share has been trading — unusual movement, volume or concentration — rather than by any finding against the company. It is a signal to look more carefully, not a conclusion.
How do I avoid getting stuck in an illiquid stock?
Look at ordinary daily turnover across a quiet month rather than on an exciting day, check the gap between buy and sell prices, and size the position against that rather than against your conviction. Also check whether the share currently sits on either exchange's surveillance list before buying.
Related Reading
- Verifying who you are dealing with
- What a stop-loss order actually does
- The spread, and why liquidity costs money
- Which companies move the index
- The beginners course, for Kolkata
- Risk and position sizing, taught properly
Disclaimer: TheFinBaba provides educational content only - this is not investment advice. Trading involves risk of loss.
