Standard deviation is a metric that shows the variability of a security’s returns over time. It can be used to gauge volatility based on past performance and compare a future return to past returns.

How They Differ and Practical Uses in Finance and Investing Henry Hoenig has three decades of journalism experience as a news and economics editor in the U.S. and Asia, handling coverage of global ...

Andrew Bloomenthal has 20+ years of editorial experience as a financial journalist and as a financial services marketing writer. Samantha (Sam) Silberstein, CFP®, CSLP®, EA, is an experienced ...

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In response to my article, Is the Stock Market Too Concentrated?, which relied upon standard-deviation calculations to assess investment risk, a reader wrote: “My problem [with your argument] is ...