Volatility (Volatility · VIX)
How much a stock price swings up and down — the larger it is, the greater the uncertainty and fear. The volatility gauge for the whole market is the VIX (the "fear index").
Volatility = measured by how widely stock returns scatter around their average (standard deviation)
High volatility isn't automatically a bad thing.
In plain terms
Volatility is how sharply a stock price swings up and down. If one stock moves 1% a day and another moves 10% a day, the latter has higher volatility.
The best-known gauge of volatility for the whole market is the VIX. The more anxious investors are, the higher the VIX climbs, which is why it is also called the "fear index." It is low when markets are calm and spikes during sharp selloffs.
What it tells you
Volatility is a yardstick for gauging "the size of the risk." For the same expected return, higher volatility means more nerve-wracking moments and a greater chance of short-term losses.
A sharp spike in the VIX signals that fear has spread through the market, and it often shows up alongside steep selloffs. On the flip side, a very low reading is sometimes read as the market being complacent.
Formula
Volatility = measured by how widely stock returns scatter around their average (standard deviation) VIX = expected volatility over the next 30 days, estimated from S&P 500 options (the "fear index")
What high or low means
High volatility isn't automatically a bad thing. It's a phase where both risk and opportunity grow larger. That said, it's far from a comfortable ride.
Highly volatile stocks (high beta) tend to rise more when the market goes up and fall more when it goes down, which is a clue for judging whether they suit your own temperament.
Volatility is about the "size of the swings," not the "direction." High volatility doesn't mean a decline is coming. It means prices can move a lot — either up or down.
Attempts to pinpoint market bottoms and tops with volatility measures like the VIX often miss. It works well as a reference for reading the mood, but it's hard to treat it as a tool for timing trades.
Volatility and the VIX are market data. This term is background knowledge for making sense of market news. (※ Our screens center on individual companies' SEC-filed financials, and price swings in a single stock are gauged with beta.)
When markets are calm, the VIX (fear index) usually sits around 10–20. But in March 2020, as the COVID-19 pandemic sent stocks plunging, the VIX topped 82 — an all-time high. It was fear on par with the 2008 financial crisis.
The market dropped more than 30% within a month, then rebounded quickly afterward. It showed that volatility is the "size of the swings," not the "direction," and that the moment fear peaks is not always the bottom or the top. That's why trying to time trades with the VIX alone is risky.
Metrics to read alongside
See it in real stocks
Search US stocks on Stocklore to see SEC-filing-based financial metrics alongside the sector benchmark.
This explanation is for information and reference only and is not a recommendation to buy or sell any security. Investment decisions and their consequences are your own.