Implied volatility (VIX)

What this actually is

A measure of how much movement option traders expect in the S&P 500 over the next thirty days, derived from option prices. It is a price for insurance, not a forecast of direction.

Why it matters to a person

A rising VIX forces mechanical selling: funds that target a constant level of volatility must cut exposure when volatility rises, which pushes prices down further and raises volatility again. This is why declines accelerate rather than proceeding smoothly.

For scale

Long-run average around 19. Below 13 signals complacency; above 30 signals fear; the March 2020 peak was 82 and the 2008 peak 89. The August 2024 spike to 65 was almost entirely a positioning unwind rather than an economic event, and reversed within days.

How to read a release

The mechanism

The price of insurance; a VIX spike forces volatility-targeting funds to sell, backwardation marks a bottom more often than a top.

What to watch: VIX level; term structure; VVIX. Arrives continuous; the effect typically lasts days. Impact tier 3 — Flows and mechanics: Moves prices without changing anything fundamental, on horizons from hours to weeks. Who is forced to buy or sell, and when. Ignore this tier and market moves will regularly look inexplicable.

Primary source — cboe.com ↗