When it comes to investing in the stock market, understanding the concept of volatility is crucial. Volatility refers to the degree of price movement a stock experiences over a given period of time. Highly volatile stocks have prices that fluctuate wildly, reaching new highs and lows or moving erratically. On the other hand, stocks with low volatility maintain a relatively stable price. But why does volatility matter? Well, it is an important metric that helps traders assess the risk and potential returns of a particular investment.
In this article, we will explore various measures of stock price volatility and discuss their significance in investment decisionmaking. We will delve into metrics such as standard deviation, Bollinger Bands, maximum drawdown, and beta. Each of these measures provides unique insights into a stock’s volatility and can be used to inform trading strategies. So, let’s dive in and discover the best measure of stock price volatility!
Standard Deviation: The Most Common Measure of Volatility
The primary measure of volatility used by traders and analysts is standard deviation. It reflects the average amount a stock’s price has differed from the mean over a specific period of time. Standard deviation is calculated by determining the mean price for the established period and then subtracting this figure from each price point. The differences are then squared, summed, and averaged to produce the variance. The formula for standard deviation is as follows:
Standard Deviation = √[Σ(xi  x̄)^2 / (n1)]
Let’s break down the components of this formula:

xi
: Value of the ith point in the data set 
x̄
: The mean value of the data set 
n
: The number of data points in the data set
The standard deviation is calculated in a few steps:

Find the mean of all data points by adding all data points and dividing by the number of data points.

Find the variance of each data point by subtracting each data point from the mean.

Square each variance, then add all squared variances together.

Divide the sum of squared variances by one less than the number of data points.

Take the square root of the variance; this is the standard deviation.
By taking the square root of the variance, the standard deviation is brought back to the same unit of measure as the underlying data set, making it easier to interpret.
Standard deviation is widely used because it provides a comprehensive measure of a stock’s price volatility. Traders can rely on this metric to understand the range within which a stock’s price is likely to fluctuate. A higher standard deviation indicates greater volatility, while a lower standard deviation suggests stability. However, it’s important to note that standard deviation alone may not provide a complete picture of a stock’s volatility. That’s where other measures, such as Bollinger Bands, come into play.
Bollinger Bands: Analyzing Volatility Over Time
Chartists and technical analysts often use a popular technical indicator called Bollinger Bands to analyze standard deviation over time. Bollinger Bands consist of three lines: the simple moving average (SMA) and two bands placed one standard deviation above and below the SMA. The SMA represents a smoothedout version of the stock’s historical price, but it is slower to respond to changes.
The outer bands mirror price changes, reflecting the corresponding adjustment to the standard deviation. The width of the Bollinger Bands indicates the level of volatility within a given period. Wider bands suggest higher volatility, while narrower bands indicate lower volatility.
Let’s take a look at an example to better understand how Bollinger Bands work. In the chart above, we can see a sixmonth range of Snap Inc. (SNAP) with Bollinger Bands enabled. For the most part, the stock traded within the tops and bottoms of the bands. The price ranged between approximately $12 and $18 per share. Bollinger Bands are often used as an indicator of the range within which a security trades. The upper band limit indicates a potentially high price to sell at, while the lower band limit suggests a potential low price to buy at.
Bollinger Bands provide traders with a visual representation of a stock’s volatility, making it easier to identify periods of high or low volatility. By examining the width of the bands, traders can gauge the potential for price swings and adjust their trading strategies accordingly.
Maximum Drawdown: Measuring Historical Losses
Another important measure of stock price volatility is maximum drawdown. Maximum drawdown measures the largest historical loss for an asset, from its peak to its trough, over a specific time period. It allows traders and investors to understand the potential downside risk associated with a particular investment.
Maximum drawdown can be useful for speculators, asset allocators, and growth investors who want to limit their losses. By focusing on the largest historical loss, investors can determine their risk tolerance and make informed decisions about their portfolio allocations. A lower maximum drawdown indicates a more stable investment, while a higher maximum drawdown suggests greater risk.
It’s worth noting that maximum drawdown can be quoted in dollars or as a percentage of the peak value. When comparing securities, it’s important to understand the underlying prices, as dollar maximum drawdowns may not provide a fair basis for comparison. Successful growth investors, such as William J. O’Neil, often look for stocks that go up more than the market in uptrends while remaining steady during downtrends. These stocks tend to be stable because investors hold onto winners despite minor or temporary setbacks.
To limit the maximum drawdown, traders can use a tool called a stoploss order. A stoploss order automatically sells a stock or other investment when the price falls to a preset level. However, it’s important to be aware that price gaps can occur, preventing a stoploss order from executing at the desired price. Thus, it’s crucial to consider the potential limitations of using stoploss orders as a risk management tool.
Beta: Volatility Relative to the Market
Beta is another measure of volatility that compares a security’s price movements to those of the broader market. A beta of 1 means that the security has volatility that mirrors the degree and direction of the market as a whole. If the S&P 500, for example, experiences a sharp dip, a stock with a beta of 1 is likely to follow suit by falling a similar amount.
Stocks in stable sectors, such as utilities, typically have beta values of less than 1, indicating lower volatility compared to the broad market. Conversely, stocks in rapidly changing fields, especially in the technology sector, often have beta values greater than 1, signifying higher volatility. A beta of 0 suggests that the underlying security has no marketrelated volatility. For example, cash (assuming no inflation) is an asset with a beta of 0.
Beta is a useful metric for evaluating the relative risks of different stocks or determining the diversification benefits of other asset classes. By understanding a stock’s beta, investors can assess how closely the stock’s price movements align with market trends. This information can help them make informed decisions about portfolio allocation and risk management.
CBOE Volatility Index (VIX): Measuring Expected Volatility
The CBOE Volatility Index (VIX), often referred to as the “fear index,” is a widely used metric for measuring the expected volatility of the S&P 500. The VIX reflects market participants’ expectations of future volatility over the next 30 days. It is calculated based on the prices of options on the S&P 500 index.
The VIX is often seen as a measure of investor sentiment and market fear. A higher VIX value indicates increased expected volatility, reflecting greater uncertainty and potential market downturns. Conversely, a lower VIX value suggests lower expected volatility and a more stable market environment.
Traders and investors use the VIX to assess market conditions and make informed decisions about their trading strategies. A VIX value above 30 is generally considered relatively volatile, while a value below 20 is associated with a lowvolatility environment. It’s important to note that the longterm average for the VIX has been slightly above 20.
Is High or Low Volatility Better for Stocks?
The level of volatility that is considered better for stocks depends on the investment strategy and risk tolerance of the trader or investor. Day traders often favor highvolatility stocks because they provide more opportunities for large swings and quick profits within short periods of time. On the other hand, longterm buyandhold investors usually prefer low volatility, as it offers incremental and steady gains over time.
When overall volatility in the stock market is rising, it can signal increased fear and uncertainty among investors. This may lead to a potential market downturn. Traders and investors should closely monitor volatility levels and adjust their strategies accordingly.
What Is Considered Average Stock Volatility?
When looking at the broad stock market, there are various ways to measure average volatility. One commonly used measure is beta. Since the S&P 500 index has a reference beta of 1, a beta of 1 is considered the average volatility of the market. Beta values higher than 1 indicate higher volatility, while values lower than 1 suggest lower volatility compared to the market.
Another measure of average stock volatility is the CBOE Volatility Index (VIX). The VIX measures the average volatility of the S&P 500 on a rolling threemonth basis. Traders often consider a VIX value above 30 to be relatively volatile and a value below 20 to indicate a lowvolatility environment. The longterm average for the VIX has been slightly above 20.
Trading Changes in Volatility
For those looking to speculate on volatility changes or hedge existing positions, there are several options available. One option is to trade VIX futures and exchangetraded funds (ETFs) that track volatility. These instruments allow traders to directly participate in the volatility market and take advantage of volatility fluctuations.
Additionally, options contracts are priced based on the implied volatility of stocks or indices. Traders can use options to make bets on or hedge against volatility changes. Implied volatility is determined using computational models such as the BlackScholes Model or the Binomial Model. These models identify factors that may impact an equity’s future price, determine outcome likelihoods, and price derivative products like options based on their findings.
Traders and investors should carefully assess their risk tolerance and market outlook before engaging in volatility trading strategies. It’s important to understand the potential risks and rewards associated with trading changes in volatility.
Why Is Stock Volatility Important?
Stock volatility plays a crucial role in investment decisionmaking. It is an indicator of fear or uncertainty in the market and can provide insights into potential market downturns. Prices tend to swing more wildly when investors are unable to make sense of economic news or corporate data. An increase in overall volatility can be a predictor of a market downturn.
Moreover, volatility is a key component in pricing options contracts. Options prices are influenced by the expected volatility of the underlying stocks or indices. Higher volatility leads to higher option prices, as there is a greater likelihood of large price swings.
By understanding stock volatility, traders and investors can better assess risk, make informed investment decisions, and implement appropriate risk management strategies.
Conclusion
In conclusion, understanding stock price volatility is essential for successful investing. While there are various measures of volatility, the most common measure is standard deviation. It provides a comprehensive view of a stock’s price movements and helps traders assess risk. Bollinger Bands, maximum drawdown, and beta are additional measures that offer unique insights into a stock’s volatility.
Traders can also monitor the CBOE Volatility Index (VIX) to gauge expected market volatility. The level of volatility that is considered better for stocks depends on the investment strategy and risk tolerance of the trader or investor.
It’s important to remember that stock volatility can be both a risk and an opportunity. Traders can hedge to minimize the impact of volatility on their portfolio, or they can embrace volatility and seek to profit from price swings. By understanding and effectively managing volatility, traders and investors can navigate the stock market with confidence.