Trading & Stock Market Basics
What Is ASM in Stock Market? Meaning, Purpose & Impact on Trading
Aug 21, 2025
In the Indian stock market, investor safety and fair trading practices are maintained through various regulatory measures. One such measure is the ASM in stock market, introduced by the Securities and Exchange Board of India (SEBI) along with stock exchanges. Additional Surveillance Measure (ASM) is designed to keep a close watch on certain stocks that may show unusual price movements or volumes, often without corresponding business fundamentals.
This mechanism helps protect you (investor) from potential risks arising from speculative activities and ensures the market remains transparent and orderly.
ASM Meaning in Share Market
ASM meaning in share market refers to a regulatory framework that imposes additional surveillance on specific securities. The purpose is not to label a company as weak or fraudulent, but to ensure investors are cautious while dealing in these stocks.
When a stock is placed in the ASM list, it means that exchanges like NSE and BSE have noticed unusual patterns, such as sudden price spikes, sharp volatility, or irregular trading volumes. They are compared with the market average, and these stocks will require closer monitoring before you decide to invest or trade.
Why ASM in Stock Market Was Introduced
SEBI had introduced it, the primary aim of ASM in stock market is to:
- Protect retail investors from speculative trading activities that can lead to sudden losses.
- Discourage manipulative practices by monitoring abnormal price and volume changes.
- Promote transparency so that investors have clear information before making decisions.
Regulators try to have a level playing field by implementing ASM, especially for small investors who may not always have access to in-depth market analysis.
Key Criteria for Placing a Stock Under ASM
Exchanges use specific parameters to decide if a stock should be part of the ASM list in share market. These can include:
- High price-to-earnings (P/E) ratio compared to peers.
- Unusual volatility over a short period.
- Sudden changes in market capitalization.
- Abnormal delivery percentage (high or low).
- Price variation without significant news or business developments.
The NSE ASM list is updated periodically and published on the official exchange websites. This transparency ensures investors can check the status of a stock before trading.
Types of ASM Framework
ASM in the stock market is implemented in two stages:
- Long-Term ASM: Targets stocks showing prolonged abnormal trading behaviour
- Short-Term ASM: Monitors stocks with sudden, sharp price movements or spikes in volumes over a brief period.
The framework allows exchanges to adjust surveillance levels depending on the severity of the trading irregularities.
What Happens When a Stock Is Under ASM?
When a stock is placed under ASM, certain trading conditions may be applied, such as:
- Higher margin requirements for traders.
- Trade-to-trade settlement, meaning intraday trading is not allowed; delivery of shares is mandatory.
- Reduced price bands to limit daily fluctuations.
These measures do not indicate that the stock is fundamentally weak, but they make it harder for speculative traders to manipulate prices.
Impact on Investors and Traders
When a stock is on the ASM list in share market, it can influence market perception. Retail investors often see ASM as a cautionary signal and may reduce their exposure to such stocks. On the other hand, long-term investors might not be overly concerned if they believe in the company's fundamentals.
For traders, ASM means restricted opportunities for quick gains through intraday positions. The extra margins and delivery-based trading requirements can reduce liquidity in the short term.
How to Check if a Stock Is in ASM
Investors can visit the official websites of NSE and BSE to view the NSE ASM list or the BSE ASM list. You will have to keep a check on this list as they are updated periodically, and the exchanges provide detailed notes on why certain securities have been included.
ASM Is Not a Judgment on Company Quality
You should note that an ASM in stock market is not a declaration that the company is facing trouble or engaging in fraudulent activities. It is purely a preventive measure to ensure fair market practices. You may also see some fundamentally strong companies appear on the ASM list due to temporary market trends, news events, or sudden investor interest.
Conclusion
ASM in stock market is to safeguard all investors and maintain market discipline. When you understand its meaning, purpose, and impact, you can make informed decisions and avoid unnecessary risks. Whether you are a retail investor or an active trader, staying updated with the NSE ASM list can help you navigate the market more prudently. You can find more information like this on Indiabulls Securities Limited (formerly Dhani Stocks).
FAQs on ASM in Stock Market
1. What is ASM in stock market?
Additional Surveillance Measure (ASM) is a regulatory framework used by exchanges to monitor stocks showing unusual price or volume movements.
2. Does ASM mean a company is in trouble?
No. ASM meaning in share market does not imply a company is financially weak. It is only a preventive measure for investor protection.
3. How can I find the ASM list in share market?
You can check the NSE ASM list or the BSE ASM list on their respective official websites.
4. Can I trade in ASM-listed stocks?
Yes, but trading conditions may be stricter, such as higher margins and trade-to-trade settlement.
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