The VIX (Volatility Index)
The VIX is often called the market’s "fear gauge". It is a single number, published by Cboe, that captures the volatility the options market expects in the S&P 500 over the next 30 days. When investors are calm the VIX is low; when they are scared and rushing to buy protection it spikes. Understanding what the VIX actually measures — and what it does not — is one of the most useful things an options trader can learn.
Open the Protective Put calculator →What the VIX actually measures
The VIX is not the volatility that has already happened — it is implied volatility, backed out of the prices of S&P 500 (SPX) options. When traders pay up for options they are signalling that they expect bigger moves, and the VIX rises; when option premiums are cheap, it falls. It is quoted as an annualised percentage: a VIX of 16 means the market expects roughly a 16% move over the next year, or about 4.6% over the coming month.
Crucially it says nothing about direction. A high VIX means the market expects large moves, not down moves — though in practice fear and falling prices tend to arrive together, which is why the VIX usually spikes when stocks drop.
How to read it
As a rough guide, a VIX under about 15 signals calm, complacent markets; the high teens to low 20s is normal; above 30 signals real fear; and spikes above 40–50 accompany crises and crashes. These are not hard lines, but they let you read the market’s mood at a glance.
Because the VIX tends to rise when the S&P 500 falls, it is negatively correlated with stocks and is watched as a contrarian gauge: extreme highs have historically clustered near market bottoms (peak fear), while very low readings can flag complacency before a pullback.
Can you trade the VIX?
You cannot buy the VIX index itself — it is just a calculation. But you can trade instruments based on it: VIX futures, VIX options and exchange-traded products such as VXX or UVXY. These are powerful but treacherous — they track VIX futures, not the spot index, and the futures curve usually costs money to hold (contango), so long-volatility products bleed value over time and suit short-term hedges, not buy-and-hold.
For most traders the VIX is best used as a context tool: high implied volatility (a high VIX) makes option-selling strategies more attractive because premiums are rich, while low volatility favours buying options. It tells you, at a glance, how expensive options are right now across the whole market.
- The VIX is the options market’s expected 30-day volatility of the S&P 500 — implied, not realised.
- It measures the size of expected moves, not their direction; it usually spikes when stocks fall.
- Rough zones: under 15 calm, high-teens normal, above 30 fear, above 40 crisis.
- You trade it via futures/options/ETPs, which track VIX futures and decay — tools for short-term hedging, not holding.
Frequently asked questions
What is the VIX in simple terms?
It is a single number showing how much volatility the options market expects in the S&P 500 over the next 30 days. A high VIX means traders expect big moves and are paying up for protection; a low VIX means they expect calm.
What is a high or low VIX?
As a rough guide, below about 15 is calm, the high teens to low 20s is normal, above 30 signals real fear, and spikes above 40 accompany crises. There are no hard cut-offs, but these zones capture the mood.
Can I buy the VIX?
Not directly — it is a calculated index. You can trade VIX futures, VIX options or products such as VXX and UVXY, but these track VIX futures rather than the spot index and tend to lose value over time, so they are tools for short-term hedging, not long-term holding.
Implied Volatility ExplainedVolatility Skew and the Volatility SmileTheta Decay & Selling Premium
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