The CBOE measure of expected implied volatility in S&P 500 over 30 days, computed from SPX. option prices. Below 15 = calm and comfort. 15–25 = normal. Above 30 = worry and fear. Above 40 = panic.
What it really measures
The VIX index measures the Implied Volatility expected for the S&P 500 index over thirty days, extracted from the prices of its options. It is not a measure of decline by itself but of the size of the move being priced. Still, fear is tied to insurance buying, so it jumps several times more on a drop than it moves on a rise, and earned the nickname fear gauge.
Reading zones
Below 15 is deep calm (maybe too much comfort), between 15 and 20 is normal, between 20 and 30 is rising tension, above 30 is open fear, and above 40 is a historic type of panic. More important than the level is how it behaves: a sharp rise from a quiet low has warned many times before the story played out in prices.
Its term structure says more
Comparing VIX (thirty days) with its longer-dated counterpart shows the state. Longer-dated higher (Contango) is the usual healthy setup. Inverted, with the near term above the far term, is a sign of sharp, immediate stress, and this inversion is one of the most reliable fingerprints of real panic.
Hypothetical example
A session where the index falls half a percent while VIX jumps from 14 to 19. The price move is small, but the insurance market priced in something bigger. That mismatch deserves more attention than the drop itself.
Common mistake
Trading the "number" VIX like a stock: the index itself cannot be traded, and its tradable products erode structurally over time in normal conditions. Understanding their term structure comes before any idea about them.
Where to see it on the platform
The indicator bar shows VIX live with its sparkline and status, the volatility structure beside it compares its two maturities, and the macro tools place it in the context of the overall regime.
