A stop-loss is one of the simplest risk-management tools available to investors and traders. At its core, it is a pre-decided exit point — the level at which you accept that a trade is not behaving as expected and exit rather than hold on in the hope that the trend will eventually turn in your favour.However, a stop-loss should not be a random number. It should ideally be linked to the reason you entered the position in the first place. Broadly, stop-losses can be based on three factors: price action, volatility and time.Technical-basedThis is the most common method among traders, where support and resistance levels on the chart are taken as reference points.Suppose a stock has rebounded from ₹100 on multiple occasions. This suggests strong buying interest at that level, making ₹100 an important support. If the stock approaches this level again, traders may expect buyers to step in and prevent a deeper decline.In such a case, an investor who is bullish on the stock may initiate a long position and place a stop-loss slightly below the support level, say at ₹95, allowing some room for normal market fluctuations.Similarly, stop-losses can be placed below swing lows, trendlines, moving averages or key chart patterns. Since these methods are based on market structure, they often provide more meaningful exit points.Volatility-basedMarkets do not move with the same intensity at all times. During some periods, prices can swing sharply, while at others they may move within a narrow range. Volatility-based stop-losses adjust to these changing conditions.One popular tool is the Average True Range (ATR), which measures the average price movement over a given period. Suppose a stock trading at ₹2,000 has a 14-day ATR of ₹50. A trader using a stop-loss of two times the ATR may place it about ₹100 below the entry price, around ₹1,900. To avoid obvious levels, some may place it at ₹1,880 or ₹1,885 instead.Other volatility-based tools include Bollinger Bands, Donchian Channels etc.Investors can also factor in a stock’s beta. For instance, if a stock has a beta of 2 relative to the Nifty 50 and the benchmark is expected to decline by 2 per cent, the stock could potentially fall about 4 per cent. In such cases, a stop-loss that is too tight may result in premature exits.Time-basedTime-based stops are less common and are generally used in specific situations.One example is options trading. Suppose a trader purchases a call option for ₹10,000. If the premium paid falls within the trader’s predefined risk limits, he or she may choose to hold the position until expiry. In the worst-case scenario, the option could expire worthless, resulting in the loss of the premium paid.Time-based exits can also be useful in event-driven trades. For instance, a trader may buy a stock ahead of earnings, expecting strong results. Even if the company delivers the expected numbers, the stock may fail to react positively. In such cases, the original catalyst has played out and exiting the position may be prudent.That said, time-based stops are often less precise than technical- or volatility-based approaches and are generally better suited to specific strategies.Common mistakesThe most dangerous mistake is not using a stop-loss at all. Many large trading losses occur because participants continue to hold losing positions in the hope of a recovery.Another common error is moving the stop-loss further away as the price approaches it. This often turns a manageable loss into a much larger one.Investors should also avoid determining stop-losses solely based on how much money they are willing to lose. The stop-loss should ideally be based on market structure. If the resulting risk exceeds one’s comfort level, the solution is not to move the stop-loss closer, but to reduce the position size.Finally, avoid placing stops at obvious round numbers. Such levels tend to attract large clusters of orders and may be briefly breached before the trend resumes, resulting in unnecessary exits.A useful rule of thumb is that a stop-loss should indicate when your investment or trading thesis is wrong, not merely the amount of money you are comfortable losing.Published on July 4, 2026