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LISTEN TO THE financial news, and you’ll often hear reference to “the VIX.” But what exactly is the VIX, and how important is it?
The VIX index is intended to be a measure of investor sentiment. For that reason, it’s often referred to as the market’s “fear gauge.” How can investor sentiment be measured? While the math is complex, it’s based on a straightforward principle: When investors get nervous, they look for ways to protect their portfolios and are sometimes even willing to pay for that protection. This was the insight that led to the initial development of the VIX back in 1989.
Two finance professors, Menachem Brenner and Dan Galai, observed that stock options—and specifically, the prices of those options—provided a sort of X-Ray into investors’ feelings. That’s because certain options, known as “put” options, are designed to protect portfolios from losses. They’re like insurance. So when demand for put options increases, and as a result, pushes up the prices of those options, that’s an indication that investors are feeling more nervous. On the other hand, during periods when investors are feeling optimistic, put options will fall in price. Instead, “call” options, which allow investors to magnify their gains in rising markets, will go up in price.
The relative prices of these two types of options can tell us a lot about investors’ mindset, and that’s the basis of the VIX. In very simple terms, when put option prices are rising, the VIX rises. And when put option prices are falling, the VIX falls. A higher VIX reading thus means investors are becoming more fearful.
Because of its function as a sentiment gauge, market commentators like to talk about the VIX, especially when it’s rising. But I’m not sure we should put too much stock in it. That’s for two reasons.
First, and most importantly, the VIX is limited because it’s only able to measure current investor sentiment. It doesn’t know anything about what will happen in the future. Consider how the VIX behaved during some significant market events over the past 20 years.
In August 2008, the VIX was at a relatively low level, right around 20. It seemed to be indicating calm seas. But just a month later, Lehman Brothers went into bankruptcy, and the stock market began to fall. The VIX did eventually spike up in response to this crisis, ultimately rising all the way to 80—a very high reading—but by that point, it was too late. It was effectively reporting yesterday’s news.
At other points, the VIX has been misleadingly high. In the spring of 2020, when the market dropped more than 30%, fear levels were running high, and the VIX spiked up to 82. But with the benefit of hindsight, we can see that the VIX wasn’t communicating anything useful. That’s because the spring of 2020 would have been an ideal time to buy. Between March 16, when the VIX hit its peak, and the end of that year, the S&P 500 rose 57%. The VIX provided no hint that this rally was coming.
Nearly the same sequence of events occurred in 2025. In April, when investor worries were running high over the White House’s new tariff policies, the VIX spiked up, topping 50 on April 8. But that also would have been an ideal time to buy. A short time later, the White House changed course on tariffs, and the market rebounded, gaining 37% through the end of the year.
Why is the VIX such a poor predictor? In his book Finance for Normal People, Meir Statman describes how investors are susceptible to recency bias. He cites a Gallup survey that asked investors, “Do you think that now is a good time to invest in financial markets?” Almost invariably, investors answered “yes” when markets had been rising. In February 2000, for example, 78% of those surveyed responded positively—just a month before the market fell into a multi-year bear market. The problem is that our minds’ are prone to extrapolating from current conditions. And since the VIX simply mimics investors’ thinking, it too just extrapolates. The VIX has no idea when the market is about to reverse course, as it did in 2000, 2008 or 2025.
Despite this flaw, however, you might wonder if the VIX would nonetheless be useful as a portfolio hedge. In other words, even if the effect is delayed, the VIX seems like it might be helpful if it goes up when the market goes down, and vice versa.
In The Four Pillars of Investing, William Bernstein looks at this question. He examines a popular ETF (ticker: VXX) that tracks the VIX index. On the surface, this looks like an effective way to protect a portfolio. In the first three months of 2020, for example, when Covid arrived, and the stock market began to drop, this ETF rose more than 200%. But that was one narrow time period. Other periods were punishing for VXX. Bernstein points to 2010-2011, when the S&P 500 rose about 8.5% per year, on average. What did VXX do? You might expect that it would have fallen proportionately. But it cratered, losing 74% of its value. Bernstein asks wryly, “You didn’t expect that someone would sell you bear market insurance for free, did you?”
That, unfortunately, is the issue. Because of the way it’s constructed, the VIX doesn’t work as a perfect offset to the stock market. That’s why, in my view, investors are best served by a much simpler portfolio structure, consisting of stocks and primarily short-term Treasury bonds. While this combination isn’t flawless, it’s delivered far less volatile results over time than any strategy built around the VIX.
Like many things in finance, the VIX is interesting, but ultimately not very useful.
Adam M. Grossman is the founder of Mayport, a fixed-fee wealth management firm. Sign up for Adam’s Daily Ideas email, follow him on X @AdamMGrossman and check out his earlier articles.
Maybe I’m missing something, but it seems that the VIX is an excellent indicator. When it spikes, that seems to be a pretty good buy signal. To quote a well-known successful investor: “Be greedy when others are fearful”.
My thoughts exactly. Seems like a pretty good contrarian indicator.
Baron Rothchild advised us to “Buy when there is blood in the streets…”. Nowadays he would say “when the VIX is spiking”.
It definitely peaks my interest in buying more when the vix really spikes.
This may be important if you are a trader. But if you are an investor, you will be looking at the intrinsic value of a company compared to its market cap. If the company is selling at a significant discount, that’s a buy signal for me (and for Warren Buffett).
You describe the VIX well. The issue is that the article assumes the VIX can be used by itself to time the market.
What if I told you I already have an answer for market timing?
You shouldn’t expect one indicator, or even several, to be consistently accurate. I never did. Instead, I built a system that has helped me avoid every major market meltdown since I retired in 2018.
After hundreds of small, low-risk test trades, I came to a few key conclusions.
First: start with the big picture and decide whether the situation is truly unique.
Examples:
None of these were valuation-driven. In all of them, I was out of the market.
Second: identify when to sell as risk escalates.
I watch several real-time indicators:
This process relies heavily on experience and intuition developed from years of watching markets. It’s not based on valuations or anyone else’s opinion. All indicators must be real-time.
Third: asset class matters.
Lower-volatility categories, especially certain bond funds, are easier to monitor and trade. In my case, they’ve consistently given me at least a one-week warning before losses exceeded 1% from the most recent peak.
Finally: being wrong is part of the model.
If I’m wrong, I’m typically out for only a few days. If I’m right, I’m out for weeks (2018, 2020, 2025) or even months (January–November 2022).
You can read more (here).
Good for you, but if you keep part of it to yourself, it probably won’t work for us.
As alluded to in the comments below a high VIX may be a buy indicator. Per Warren Buffet “Be fearful when others are greedy, and greedy when others are fearful”. For me that might mean a slight adjustment to asset allocation or do nothing.
Or maybe a rebalance to your unchanged asset allocation targets.
Thanks for the Vix info. I never thought to much about it. Nice to know the quirks of it, and for my type of retirement investing, I just will not need it. At this point in life at 80, I buy the S&P 500, like VOO and IVV.
Thank you for yet another very interesting and helpful article!
You have described how to use vix to buy in the market in the article, you just don’t know it. It’s plain and simple, every time when the vix spikes to new highs that is when to buy the market and sell the market when the vix eventually drops. It worked in 2008, it worked in COVID and it worked in tariff as well. So VIX is actually the most useful and reliable indicator of the market. You just look at it in the wrong way and don’t know how to use it.
‘When covid arrived’ – no, when the hysteria arrived.
You make the VIX sound worse than useless, something meaningless as a predictor but believed in, and not particulary helpful at adding information to what we just saw happened.
A question about your useful concluding recommendation that “investors are best served by a much simpler portfolio structure, consisting of stocks and primarily short-term Treasury bonds.” Would 10 year treasuries be better based on external pressure on The Fed to lower rates. Should we be looking to lock in a 4% return?
Excellent explanation and advice, Adam.
Thanks.
Best review of the VIX I know of, thanks again Adam!
The VIX fear index was updated to S&P 500 index options in 2003 and back-calculated to 1990 to make a consistent data set. It’s a non-predictive, pants-on-fire look at a segment of technical trading that makes Chicken Little look like an optimist.
But money is on the line—lots of it—so it’s useful to me as confirmation for buying dips, such as during the tariff scare last April that I still feel all smug about. Asset allocation is everything, but I do like to have fun with less than 5% of it.
This is my plot of a 25-day moving average of the VIX to reduce the noise of the real thing (which you can see faintly in the background). Also shown is Vanguard’s S&P 500 index fund for reference.
I divided my 25-day moving average plot of VIX vs. the S&P 500 fund (above) into three date ranges for a better look at the data. Downloadable as always, Excel files are available for the asking for all the gibberish I post.
• VIX vs. VFINX 1990-2006
• VIX vs. VFINX 2007-2014
• VIX vs. VFINX 2015-2025
Very illuminating. Thank you!