VIX

The Cboe Volatility Index — nicknamed the "fear gauge" — was introduced in 1993 and originally measured expected volatility in the S&P 100. In 2003, Cboe revised the methodology to derive the VIX from a wider range of S&P 500 index options instead, the calculation still in use today.

The VIX is calculated from the prices of a broad strip of S&P 500 index call and put options expiring in roughly 30 days, using a formula that translates those option prices into an implied annualized volatility figure. In plain terms: it reflects how much price movement options traders are collectively pricing in for the S&P 500 over the coming month, not a prediction of direction — a high VIX means traders expect big swings, not necessarily a decline.

The VIX has a well-documented tendency to spike sharply during periods of acute market stress — sudden selloffs, geopolitical shocks, banking-sector stress — and then drift back down toward its long-run historical range as conditions stabilize, a pattern often described as mean reversion. It tends to move inversely to the S&P 500 itself: sharp equity selloffs are almost always accompanied by VIX spikes.

The index itself isn't directly tradeable — there's no way to buy "the VIX" the way you'd buy a stock. Investors who want exposure trade VIX futures, VIX options, or exchange-traded products built on those futures, each of which can behave quite differently from the spot VIX value shown on a quote page due to how futures pricing and roll costs work.

VIX futures typically trade in "contango" — later-dated contracts priced higher than the current spot VIX — reflecting the market's baseline expectation that volatility will drift back toward its long-run average over time. During acute market stress, that relationship can flip into "backwardation," with near-term futures pricing in more volatility than longer-dated ones, a pattern that has historically coincided with some of the sharpest equity selloffs.

Exchange-traded products built on VIX futures (such as VXX) are popular tools for retail investors seeking volatility exposure, but they're structurally prone to significant value erosion over long holding periods due to the cost of continuously rolling futures contracts in a contango market — a widely documented "volatility drag" that makes these products far better suited to short-term tactical trades than long-term buy-and-hold positions.