There is no definitive answer to this question as different investors will have different opinions on what is considered a good standard deviation for stock prices. Ultimately, it is up to the individual investor to decide what level of risk they are comfortable with and what they consider to be a good standard deviation for stock prices. Knowing the probability that a security—whether you invest in stocks, options, or mutual funds—moves in an unexpected way can be the difference between a well-placed trade and bankruptcy.

In order to ensure that your investment is secure, you need to understand what this term means and how it affects the prices of stocks. In a normal distribution, standard deviation tells you how far values are from the mean. Standard deviation is an especially useful tool in investing and trading strategies as it helps measure market and security volatility—and predict performance trends. As it relates to investing, for example, an index fund is likely to have a low standard deviation versus its benchmark index, as the fund’s goal is to replicate the index. When it comes to investing, investors can reasonably expect an index fund to have a low standard deviation because the whole goal of an index fund is to match the index.

A stock with high volatility generally has a high standard deviation, while the deviation of a stable blue-chip stock is usually fairly low. If you look at the distribution of some observed data visually, you can see if the shape is relatively skinny vs. fat. Alternatively, Excel has built in standard deviation functions depending on the data set. If the data behaves in a normal curve, then 68% of the data points will fall within one standard deviation of the average, or mean, data point.

Because it is easy to understand, this statistic is regularly reported to the end clients and investors. Standard deviation in investing usually appears in the likeness of Bollinger bands. Bollinger bands, created by John Bollinger in the 1980s, are a number of lines that assist in determining trends in specific stocks. The exponential moving average (EMA) is found at the center of these trend lines, and it shows the average price of the stock over a given period of time.

- The standard deviation of two data sets can be combined using a specific combined standard deviation formula.
- It’s not uncommon for charts that typically see narrow bands to experience random spikes in volatility — for example, after earnings reports or products are released.
- Traders and analysts use a number of metrics to assess the volatility and relative risk of potential investments, but one of the most common metric is standard deviation.
- The investing information provided on this page is for educational purposes only.

Traders and analysts use a number of metrics to assess the volatility and relative risk of potential investments, but one of the most common metric is standard deviation. Standard deviation is the statistical measure of market volatility, measuring how widely prices are dispersed from the average price. If prices trade in a narrow trading range, the standard deviation will return a low value that indicates low volatility. Conversely, if prices swing wildly up and down, then standard deviation returns a high value that indicates high volatility. A historical standard deviation is a statistical measure of how much past stock prices have fluctuated.

## Standard Deviation Investments

Conversely, a stock with a low standard deviation is less likely to see sharp price movements, making it a safer investment but also one with less potential for gain. While standard deviation is an important measure of investment risk, it is not the only one. There are many other measures investors can use to range trading versus trend following determine whether an asset is too risky for them—or not risky enough. When prices swing up or down significantly, the standard deviation is high, meaning there is high volatility. On the other hand, when there is a narrow spread between trading ranges, the standard deviation is low, meaning volatility is low.

## How does the standard deviation of stock prices affect investors

That’s because it can be assumed—with relative certainty—that they continue to behave in the same way. A security with a very large trading range and a tendency to spike, reverse suddenly, or gap is much riskier, which can mean a larger loss. There are inherent risks involved with investing in the stock market, including the loss of your investment. Past performance in the market is not indicative of future results. This also means that 5% of the time, the stock’s price can experience increases or decreases outside of this range. When the stock’s standard deviation is high, it is most likely a highly volatile stock.

## What is the standard deviation of stock prices

Using the standard deviation, statisticians may determine if the data has a normal curve or other mathematical relationship. The greater the standard deviation of securities, the greater the variance between each price and the mean, which shows a larger price range. For example, a volatile stock has a high standard deviation, while the deviation of a stable blue-chip stock is usually rather low. Standard deviation is a statistical measurement in finance that, when applied to the annual rate of return of an investment, sheds light on that investment’s historical volatility.

## Calculating standard deviation

When the volatility lessens, the bands will fall closer together and appear nearer to the exponential moving average. It’s not uncommon for charts that typically see narrow bands to experience random spikes in volatility — for example, after earnings reports or products are released. A mutual fund with a long track record of consistent returns will display a low standard deviation. A growth-oriented or emerging market fund is likely to have greater volatility and will have a higher standard deviation. This measurement of average variance has a prominent place in many fields related to statistics, economics, accounting, and finance. For a given data set, standard deviation measures how spread out the numbers are from an average value.

If the asset has a standard deviation of, say, 5%, then most of the time the returns would be expected to deviate from that 10% average between plus or minus 5%. So, from 10%, you may commonly see 5% to 15% returns as well under the standard deviation. If the standard deviation was 15%, then the asset would be expected to have https://www.day-trading.info/what-is-a-flash-crash-stock-market-crashes-how/ more volatility, as returns on an asset averaging 10% in this case could also commonly range from -5% to 25%. The variance helps determine the data’s spread size when compared to the mean value. As the variance gets bigger, more variation in data values occurs, and there may be a larger gap between one data value and another.

A low historical standard deviation means that a stock’s price hasn’t fluctuated much in the past. This could mean that the stock is less risky than other stocks, and https://www.topforexnews.org/investing/should-you-invest-in-crypto/ that its price is less likely to change dramatically in the future. So, there is definitely a relationship between risk and the standard deviation of stock prices.