Volatility
InvestmentsVolatility measures how much an investment's returns vary over time. High volatility means large swings in value; low volatility means stable, predictable returns. Equity is high-volatility; government bonds and FDs are low-volatility. Volatility is the price paid for higher long-term returns.
In detail
Standard deviation is the statistical measure of volatility: Nifty 50 annual standard deviation is approximately 20-25%, meaning returns in any given year could be 20-25% above or below the average. An FD has near-zero volatility -- you know exactly what you get.
Volatility is not the same as risk (permanent loss). Nifty 50 is highly volatile but has always recovered to new highs over 5-7 year periods. The true risk is not short-term price swings -- it is making poor decisions (selling during downturns) because of volatility.
Key insight: volatility is an investor's emotional test. Those who stay invested through volatile periods generate the market return. Those who sell during downturns lock in losses and miss the recovery.
Formula
Real-life example
Nifty 50 in 2020: fell from 12,000 to 7,500 (-37.5%) in March. By December 2020, back to 13,900 -- up 85% from the March low and 16% for the year. An investor who panic-sold at 7,500 and bought back at 12,000 lost 37.5%. An investor who stayed invested from 12,000 to 13,900 gained 16%. Same market, opposite outcomes -- determined entirely by behaviour during volatility.