ASM and GSM Framework on NSE: What Each Stage Really Means

You log in to buy a stock you have been tracking for weeks. Suddenly your broker demands 100% of the money upfront, intraday trading is switched off, and the price refuses to move more than 5% in a day. You did nothing wrong — the stock did. It has been placed under surveillance. Understanding the ASM and GSM framework on NSE is what separates traders who get blindsided by these restrictions from those who see them coming. This guide breaks down every surveillance stage, why stocks land there, and how to check a stock before your capital gets locked in.

Why NSE puts stocks under surveillance

India's exchanges — NSE and BSE — run a set of monitoring systems designed by SEBI and the exchanges to protect ordinary investors from price manipulation and bubbles. When a stock behaves in a way that looks unusual, the exchange does not ban it. Instead, it applies graduated restrictions that make speculation expensive and slow, while still letting genuine investors buy and sell.

There are three main frameworks a retail trader will meet: the Additional Surveillance Measure (ASM), the Graded Surveillance Measure (GSM), and the Enhanced Surveillance Measure (ESM). They sound similar and their consequences overlap, but they are triggered by very different things. ASM watches how a stock is traded. GSM watches whether the price makes sense given the company's fundamentals. ESM focuses on the smallest companies where a little money can move the price a lot.

The reason this matters to you is simple: surveillance changes the rules of the game mid-play. Your margin goes up, your leverage disappears, and in the worst stages you can only trade the stock once a week. If you learned how markets work from scattered videos rather than a structured path, these are exactly the gaps that trip you up — a structured stock market training program teaches you to read these signals before they cost you money.

ASM: the Additional Surveillance Measure

ASM is triggered by trading behaviour, not by the company itself. According to NSE's own framework, the parameters include sudden high-low price variation, close-to-close price swings, a jump in volume, a high concentration of buying among a few clients, and a low delivery percentage (a sign that trades are speculative rather than genuine). A perfectly healthy, profitable company can land in ASM simply because its stock ran up too fast on thin, concentrated trading.

ASM comes in two flavours.

Short-Term ASM (ST-ASM)

This is the lighter, temporary measure. Since September 2024 it functions mainly as an increased margin requirement — there is no shift to trade-for-trade settlement and no change to the price band. It is reviewed weekly and usually lasts from a week to a month. To give a sense of scale, in April 2026 NSE placed 19 securities under ST-ASM Stage I with a 50% margin requirement, and additional securities under Stage II at 100% margin.

Long-Term ASM (LT-ASM)

This is the heavier version, and it runs through four stages, I to IV. Across all LT-ASM stages a 100% margin applies and intraday trading is blocked — you must take delivery. As the stage rises, the price band tightens, and by Stage IV the stock is moved to trade-for-trade (the "BE" series), meaning every single trade must be settled by delivery with no intraday netting at all. A stock must stay in the framework for a minimum of 90 days before it can exit, so this is not a one-day inconvenience.

GSM: the Graded Surveillance Measure

Where ASM watches trading, GSM watches fundamentals. It targets companies whose share price cannot be justified by their financial health. A stock becomes eligible when, for example, its net worth is ?10 crore or less (₹100 million) and its net fixed assets are ?25 crore or less (₹250 million), or when it has a negative price-to-earnings ratio, or a P/E more than twice that of the benchmark Nifty 500 or S&P BSE 500 index. In plain terms: tiny company, weak balance sheet, but a share price flying for no fundamental reason.

GSM currently runs through four graded stages, and each one clamps down harder than the last. The key lever is the Additional Surveillance Deposit (ASD) — a deposit the buyer must post, which is blocked with the exchange for months. It is the market's way of saying: if you want to keep buying this, put serious money on the table first.

Here is how the ladder typically works. At Stage I, the stock gets a tight 5% price band and daily trading continues, but it is flagged for everyone to see. From Stage II and III, it moves to trade-for-trade with a 5% band and the buyer must post a deposit of 50% to 100% of trade value. By Stage IV, trading can be restricted to once a week, the deposit reaches up to 200%, and a "no upward price movement" rule can apply — the price is simply not allowed to rise further. At that point the stock is effectively frozen for speculation.

ASM vs GSM vs ESM: how to tell them apart

Because the three measures share tools — higher margins, tighter bands, trade-for-trade — traders often confuse them. The quickest way to keep them straight is to remember what each one is actually looking at: ASM looks at trading activity, GSM looks at the balance sheet, and ESM looks at company size plus volatility. The table below lays out the practical differences.

What to do if your stock enters surveillance

Discovering a holding has entered ASM, GSM or ESM is unsettling, but panic-selling into a 5% band is usually the worst response. Here is a calmer sequence to follow.

• Find out exactly where it sits. NSE and BSE publish daily surveillance lists showing every stock, its framework, and its stage. Your broker's terminal usually flags the series code too (for example, a "BE" or "BZ" suffix signals trade-for-trade).
• Separate the noise from the signal. ASM is often temporary and about trading froth, so a genuinely strong company can recover. GSM is a fundamentals warning — treat it far more seriously, because the exchange is telling you the price may not be backed by real value.
• Respect the lock-in. With a 90-day minimum stay and a possible weekly-trading restriction, assume your money could be stuck and illiquid for months. Never put capital you might need soon into a surveillance stock.
• Do not average down blindly. A "no upward price movement" rule at the top GSM stage means there may be no quick rebound to save a losing position.

The recurring lesson is that most surveillance shocks are avoidable with a little homework. Wildly outperforming penny stocks, thinly traded names, and companies with weak balance sheets are exactly the profiles these frameworks catch. We break down how to read the fundamentals that GSM cares about in our guide to the financial ratios to check before buying any stock, and why market-cap size matters in large-cap vs mid-cap vs small-cap investing.

What this means for how you pick stocks

The ASM and GSM framework on NSE is not your enemy — it is a free, daily risk filter built by the exchange. If a stock you are about to buy is already under surveillance, the market is handing you a warning label. The disciplined move is to read it, not ignore it.

Build two quick habits. First, before buying any unfamiliar stock, glance at the exchange surveillance list — it takes thirty seconds and can save you from a locked, illiquid position. Second, learn to spot the profiles that attract surveillance before the flag is even raised: unjustified price spikes, tiny net worth, and a price band already tighter than its peers, which ties directly into how circuit limits and price bands work. Master those and you will rarely be surprised again.

Frequently Asked Questions

What is the difference between ASM and GSM on NSE?

ASM (Additional Surveillance Measure) is triggered by unusual trading activity — sharp price moves, volume spikes, low delivery, or concentrated buying. GSM (Graded Surveillance Measure) is triggered by weak fundamentals, such as a small net worth or a share price far higher than earnings justify. In short, ASM watches how a stock trades; GSM watches whether its price makes sense.

Can I do intraday trading in an ASM or GSM stock?

Usually not. Across all Long-Term ASM stages intraday is blocked and you must take delivery. Under GSM, intraday is generally permitted only at Stage I, and from Stage II the stock moves to trade-for-trade settlement where every trade must be settled by delivery. ESM allows intraday only in Stage I.

What is the 100% margin rule in surveillance stocks?

It means you must pay the full value of the trade upfront with no leverage or exposure from your broker. If you want to buy ₹1 lakh of the stock, you need ₹1 lakh in your account. Under higher GSM stages, the buyer may also post an Additional Surveillance Deposit of up to 200% of trade value, which stays blocked for months.

How long does a stock stay under the ASM or ESM framework?

There is a minimum stay of 90 days before a stock can be reviewed for exit, and stages are reviewed periodically (weekly for short-term measures). A stock only exits once it stops meeting the entry criteria across the review window, so surveillance is usually a matter of months, not days.

Is a stock under GSM a bad investment?

Not automatically, but it is a serious caution flag. GSM specifically targets companies whose price is not supported by fundamentals, so the burden is on you to prove the business is sound before buying. Many GSM stocks are illiquid small companies, and the trading restrictions make it hard to exit quickly — treat them with far more care than a normal stock.

Where can I check if a stock is under surveillance?

NSE and BSE both publish daily surveillance lists on their websites showing every stock under ASM, GSM and ESM along with its current stage. Most broking terminals also display the applicable series code and margin, so you can check before you place an order rather than after your capital is locked.

Disclaimer: This article is for educational purposes only and does not constitute investment advice. Markets carry risk — please do your own research or consult a qualified financial professional before investing. NIFM provides training and exam preparation; certification exams conducted by regulatory or professional bodies are administered by those bodies independently.