The VIX, Explained: What It Measures, What a Normal Level Is, and What the S&P 500 Did After Every VIX Close Since 1990

The VIX is the market's estimate of how much the S&P 500 will move over the next 30 days, read off the prices of S&P 500 options. It closed at 16.68 on October 21, 2026, which translates to an expected daily move of about 1.1% and a 30-day range of roughly plus or minus 4.8%. That is what the number means. What it has been worth knowing is a different question, so we took every VIX close since the index began in January 1990, 9,269 trading days, matched each to the S&P 500, and measured what the market did at each level: the size of the day's moves, the next month, quarter and year, the worst drawdown that followed, and how long every spike above 30 took to calm down. The short version: a high VIX has described a rough present and, on average, a better-than-usual year ahead, which is the opposite of how most people trade it. Education, not advice.

What is the VIX?

The Cboe Volatility Index, ticker VIX, is a number published by Cboe Global Markets every few seconds during the trading day. It is calculated from the prices of S&P 500 index options expiring between 23 and 37 days out, weighted to a constant 30-day horizon, using the methodology Cboe published in 2003. You cannot buy the VIX itself; you can trade futures and options on it, and a family of exchange-traded products tracks those futures, which is a different thing from the index and the reason those products behave the way they do.

The number is an annualized volatility. To turn it into something usable, divide by the square root of 252 trading days for an expected one-day move, or multiply by the square root of 30/365 for the 30-day range the options are pricing. At a VIX of 20, the implied daily move is about 1.3% and the 30-day range is about plus or minus 5.7%. At 40, double both. The options market is not promising those moves; it is charging for them.

What is a normal VIX level?

The median VIX close since 1990 is 17.6 and the average is 19.4; the average is higher because the spikes are large and the calm stretches are long. The record close is 82.69 on March 16, 2020, in the pandemic crash, just above the 2008 peak; the lowest is 9.14 on November 3, 2017. By decade the median was 17.1 in the 1990s, 20.6 in the 2000s, 15.5 in the 2010s and 18.6 so far in the 2020s. In 2026 the index has ranged from 14.2 to 31.0 with a median of 17.1, a calmer year than average.

The useful way to read it is by bucket. Since 1990 the VIX closed under 15 on 32% of days, between 15 and 20 on 31%, between 20 and 25 on 20%, between 25 and 30 on 9%, between 30 and 40 on 5.7%, and at 40 or above on 2.2% of days, which is 208 sessions in thirty-six years. Anything over 30 is rare, and anything over 40 has happened in only a handful of episodes.

What the VIX level says about today's move

This is the part the VIX gets right. The median size of the S&P 500's daily move was 0.32% on days the VIX closed under 15, 0.48% between 15 and 20, 0.69% between 20 and 25, 0.95% between 25 and 30, 1.27% between 30 and 40, and 2.31% at 40 and above. The share of days that moved at least 1% went from 8% in the calmest bucket to 78% in the wildest. If you want to know whether tomorrow is likely to be a big day, the VIX is the single best public number for it.

It is also, systematically, too high. Comparing each day's VIX with the volatility the S&P 500 then actually realized over the following 21 sessions, the VIX was above the realized figure 87% of the time, by a median of 4.9 points. That gap is the premium option sellers collect for insuring against the moves that usually do not come, and it is why the VIX is best read as a fear price, not a forecast.

What the S&P 500 did next, by VIX level

• One month later: the median S&P 500 return was +1.0% from days with the VIX under 15, +1.2% from 15 to 20, +1.1% from 20 to 25, +2.0% from 25 to 30, +3.6% from 30 to 40 and +3.7% from 40 and up. The market was higher a month later 65% of the time from the calmest bucket and 74% of the time from the 30-to-40 bucket.
• Three months later: +2.7%, +2.9%, +3.3%, +4.5%, +7.7% and +8.5% in the same order. Every bucket's median is positive.
• Twelve months later: +11.4%, +11.0%, +10.3%, +12.5%, +20.4% and +30.8%. From a VIX of 40 or more, the S&P 500 was higher a year later 96% of the time, the best hit rate of any bucket.

The drawdown in between: the median worst decline over the following three months was -4.1% from the calmest bucket and -13.7% from the 40-and-up bucket. The year after a panic has been good on average because it started from a low; the quarter after it was usually ugly first.

That pattern is not a buy signal, and the reason matters. The 40-and-up bucket is only 208 days, nearly all of them inside four episodes: the 2008 financial crisis, the 2010 and 2011 scares, the 2020 pandemic crash and the April 2025 tariff shock. Each ended with a recovery, so the average is good; a fifth episode could end differently, and the drawdown line says the first quarter inside one has been painful whatever came after. The bucket you actually live in is the 15-to-25 range, where the forward numbers are indistinguishable from the market's ordinary base rates.

How long does a VIX spike last?

We counted every time the VIX closed at 30 or above after a day below 30, 25 spikes since 1990, and measured how many sessions passed before it closed back under 20. The median was 52 sessions, about two and a half months. The fastest, in February 2018, December 2018, December 2021, August 2024 and March 2026, took between five and eleven sessions; the slowest, the 2008 crisis at 321 sessions and the 2020 crash at 243, took the better part of a year. The S&P 500 was higher twelve months after 13 of the 24 spikes old enough to measure; the exceptions were the 2000 to 2002 bear market and the 2007 to 2008 run-up to the crisis, when a spike was the start of the trouble rather than the end of it.

The 2026 instance is instructive. The VIX reached 31.0 in late March, was back under 20 within eight sessions, and the index went on to set records by October, which is what the fast-recovery group has usually looked like. That it recovered fast was only knowable afterward.

How to use the VIX if you trade by rules

• As a position-size dial, not a direction call. The one thing the VIX measures well is the size of tomorrow's move. If your stop is 5% away and the VIX implies a 1.1% daily move, that stop is five normal days away; at a VIX of 40 the same stop is two days away. Position sizing that scales with the VIX keeps the dollar risk of a stop-out roughly constant across regimes, which is the whole point of sizing.
• As a gap warning. A VIX above 30 means the market is pricing daily moves of 2% or more. Stops do not fill at the stop price across a gap; they fill where the market opens. Automated stops remove the delay, not the gap, so in a high-VIX regime the protection has to come from size and from a daily loss limit on the account.
• Not as a timing tool. Buying because the VIX hit 40 has a good record on paper and an awful record on nerves: the median quarter after a 40 print included a double-digit drawdown. Selling because the VIX hit 12 has no record at all; the calmest bucket's forward returns are ordinary. The drawdown history is the better guide to what you can hold through.
• Expect it to overstate. The VIX ran above realized volatility nine days in ten. A rule that pauses trading whenever the VIX crosses a round number will spend most of its time paused for storms that did not arrive. We wrote about the Fed-week version of this reflex in how to trade volatility without panic.

JorgAI reads the VIX the way this article does: it does not try to call the turn. The position cap, the stop, the profit target and the daily loss brake are set once in your own brokerage account and enforced on a 12-VIX day and a 40-VIX day alike, so the size of the move changes the outcome of a trade, never the size of the risk you agreed to. Set your rules before the next spike rather than during it.

Quick answers

What does the VIX measure? The expected volatility of the S&P 500 over the next 30 days, annualized, derived from S&P 500 option prices by Cboe. A VIX of 17 implies a daily move of about 1.1% and a 30-day range of about plus or minus 4.8%.

What is a high VIX? Anything above 30 is rare: 8% of days since 1990. The median close is 17.6. Above 40 has happened on 208 days, almost all inside the 2008, 2010 to 2011, 2020 and 2025 episodes.

Is a high VIX good or bad for stocks? Bad for the next few weeks, better than average for the next year. From VIX closes of 30 to 40 the S&P 500's median twelve-month return was +20.4%; from 40 and up it was +30.8%, higher 96% of the time. The median three-month drawdown from the 40-plus bucket was -13.7% first.

How long does it take the VIX to fall after a spike? Median 52 sessions from a close above 30 to a close back under 20, across 25 spikes since 1990. The fastest took five sessions, the slowest 321.

Does the VIX predict the market? It predicts the size of moves well and the direction poorly. It also runs above the volatility that actually follows about 87% of the time, by a median of 4.9 points.

Data: Cboe Volatility Index and S&P 500 daily closes from Yahoo Finance, January 2, 1990 through October 21, 2026, 9,269 matched sessions, our own count; forward returns are measured from the close of each day; drawdowns are the worst close-to-close decline inside the following 63 sessions; realized volatility is the annualized standard deviation of the next 21 daily log returns. Methodology from Cboe. Past patterns do not predict future returns. This article is education, not investment advice.