GlossaryGlossary

What Is the VIX? Definition and Example

The VIX is the market’s own estimate of how much the S&P 500 will swing over the next 30 days. Here is how to read it, with its long-run history.

Published Updated 2 min readHow we research

Key takeaways

  • The VIX is the Cboe Volatility Index, a measure of the S&P 500’s expected volatility over the next 30 days, implied by option prices. From 1990 to Oct 2026 its daily close averaged 19.4.
  • Its record close was 82.69 on March 16, 2020. It closed above 30 on about 8% of trading days since 1990.
  • The VIX tells you how nervous the options market is, not which way stocks will move next.

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What is the VIX?

The VIX is calculated by Cboe from the prices of S&P 500 index options. According to the Cboe VIX FAQ, it estimates expected volatility over the next 30 days and is forward‑looking, unlike historical (realized) volatility. It is often called the “fear gauge” because it jumps when investors pay up for protection.

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How do you read the VIX number?

The VIX is an annualized percentage. A rough rule: divide it by about 3.5 (the square root of 12) to get the expected one‑month move. Illustrative: a VIX of 20 implies a typical monthly move of about ±5.8% in the S&P 500 index.

What has the VIX done historically?

Exent’s calculation from FRED daily VIX closes, Jan 1990 to Oct 8, 2026:

MeasureValue
Average close19.4
Median close17.6
Record close82.69 (Mar 16, 2020)
2008 crisis peak close80.86 (Nov 20, 2008)
April 2025 tariff selloff peak close52.33 (Apr 8, 2025)
Lowest close9.14 (Nov 3, 2017)
Days closing above 30about 8%
Days closing below 15about 32%

Why it matters for a self‑directed investor

A high VIX means options are expensive and big daily moves are likely. That is useful context before you add, trim or hedge, because protection costs most exactly when you want it. See VIX hedging and the cost of hedging.

Common mistakes

  • Reading a low VIX as “safe”. The record low close of 9.14 in Nov 2017 was followed by a close of 37.32 on Feb 5, 2018.
  • Thinking you can buy the VIX itself. It is an index; VIX futures and ETFs behave differently.
  • Treating it as a direction signal. It measures expected size of moves, up or down.

Frequently asked questions

Since 1990 the VIX has had a median close of about 17.6 and an average of about 19.4. Readings above 30 have occurred on roughly 8% of days.

The highest daily close was 82.69 on March 16, 2020, during the COVID crash. The 2008 crisis peak close was 80.86.

No. A high VIX usually comes after stocks have already fallen and signals large expected moves in either direction.

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Educational content, not investment advice. Examples are illustrative; past performance does not guarantee future results.

DISCLAIMER: Exent AI is an informational research platform and does not provide investment advice, financial advice, or act as an investment adviser, broker-dealer, or fiduciary. All content, analytics, and model outputs are provided for educational and informational purposes only and should not be relied upon as a recommendation to buy, sell, or hold any financial instrument. Investing involves risk, including the possible loss of principal. Exent AI does not execute trades, hold customer funds, or provide brokerage services. Past performance and hypothetical results are not indicative of future results. Third-party data and AI-generated outputs may be incomplete or inaccurate.