Glossary
Standard Deviation
A statistical measure of how much a stock's returns vary from its average return.
Simple explanation
Higher standard deviation means the stock's price swings more wildly. More risk.
Lower standard deviation means the price moves in a tighter range. Less surprise.
It is one of the most common ways to quantify volatility in finance.
In practical terms, if a stock has an average monthly return of 2% and a standard deviation of 5%, you can expect its monthly returns to fall between -3% and +7% about two-thirds of the time. The remaining one-third, it could swing even more wildly in either direction.
Indian large-cap stocks like HDFC Bank and TCS tend to have lower standard deviations (around 20-25% annualized) compared to small-cap stocks, which can have standard deviations of 40-60% or more. This is exactly why SEBI mandates that mutual funds label their risk level, small-cap funds carry a 'Very High' risk label because of their high standard deviation.
Mutual fund factsheets in India always report standard deviation as a key risk metric. When comparing two Nifty 50 index funds or two flexi-cap funds on platforms like Groww or Kite, check the standard deviation column. A fund with a lower standard deviation delivered similar returns with fewer stomach-churning ups and downs.
As a retail investor, you do not need to calculate standard deviation yourself. Screener websites and broker apps compute it automatically. What matters is the insight: if two stocks have similar average returns but one has double the standard deviation, the steadier stock is usually the smarter pick for long-term wealth building.
Real-world example
Asian Paints has delivered average annual returns of about 18% over the past decade with an annualized standard deviation of around 25%. Compare this with Tata Motors, which also delivered strong returns but with a standard deviation of nearly 45%. If you held ₹1 Lakh in each, Asian Paints would have given you a relatively smooth ride, while Tata Motors would have had months where your ₹1 Lakh investment swung by ₹10,000-15,000 in either direction. On NSE screeners, you can compare these metrics side by side before deciding which stock suits your risk appetite.
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