Actual volatility is a measure of the real, observed price movements of a financial asset over a specific period in the past.
Understanding actual volatility
Actual volatility is calculated using historical market data. It looks backward to measure how much the price of a stock or commodity fluctuated over a given time frame. Traders calculate this metric using the standard deviation of daily returns. This provides a clear mathematical record of past price behavior.
Actual volatility reflects what has already happened, whereas implied volatility estimates future movement. Implied volatility is derived from the price of options contracts and shows the market expectation of future price swings. Actual volatility is the concrete baseline that analysts use to evaluate if current options prices are high or low compared to historical norms.
Traders across global financial markets use actual volatility to manage risk and size their positions. If an asset has high actual volatility, its price swings widely. A low actual volatility indicates a more stable price trend. Investors adjust their portfolios based on these historical metrics to match their risk tolerance.
Example
Imagine you, as Elephants, are managing a portfolio of agricultural equities on the London Stock Exchange. You want to buy shares in a global peanut supplier. To assess the risk, you calculate the actual volatility of the stock over the past 90 days. You record the closing price of the shares each day and compute the daily percentage changes. The standard deviation of these daily returns is 15 percent. This figure is the actual volatility. You then compare this 15 percent historical fluctuation against the implied volatility priced into the options market to decide if you want to buy the stock directly or hedge your position.