Staying Rational

Adam M. Grossman | Apr 18, 2026

IT’S BEEN MORE than six years since Covid first entered our vocabulary. It goes without saying that investors have experienced a lot, and for better or worse, recent market events provide some useful lessons. The first has to do with the nature of the stock market.

What drives stock prices? Open a finance textbook, and the answer will be clear: The value of a stock should equal the sum of the company’s future profits. This idea is known as intrinsic value, and it’s the textbook explanation of how stock prices work. But there’s clearly a disconnect, since stock prices bounce around far more than the math suggests they should.

How can we square this circle? Over the long term, the data tell us that intrinsic value is a valid idea. Chart the price of any given stock, then overlay the company’s profits, and there will often be a reasonably close relationship. But only if you’re Rip Van Winkle. Over shorter periods of time, anything can happen. Stocks often move far above or far below their intrinsic values in response to the news of the day.

Especially during times of economic uncertainty, intrinsic value analysis is typically cast aside and replaced by some combination of emotion, conjecture, speculation and storytelling. That’s what we saw in the early months of 2020. Stores were closed, employees had been sent home and the economy went into recession. And since no one had a crystal ball, that’s when storytellers were able to step in with their extreme predictions, causing the stock market to drop more than 30% in the space of six weeks.

The lesson for investors: No one can predict when the next crisis will roll around or what form it will take. But there is one very reasonable way to be able to keep it in perspective: by remembering that, at the end of the day, intrinsic value is what matters, and ultimately that’s what drives stock prices. Basic arithmetic illustrates how this can help us manage through the next crisis.

Consider that the price-to-earnings ratio of the U.S. stock market has historically averaged around 16. The average company’s total stock market value, in other words, has been equal to about 16 times its annual profits.

Now let’s imagine that the next crisis results in every company in America losing an entire year of earnings. That’s extreme and hasn’t happened since the Depression, but it’s useful as a thought experiment. In that scenario, what would be the impact to those companies’ intrinsic value? In simple terms, it would be just one-sixteenth, or a modest 6%. What if a crisis were so severe that a company lost two years of earnings? Using this simple model, the impact would be about 12%.

This is meaningful, I believe, because crises typically result in stock price declines that are far more severe than just 6% or 12%. In 2000 and in 2008, the market dropped more than 50%.

While every crisis is different, I think it’s useful to keep these numbers in mind whenever the next geopolitical event causes stocks to drop. When that occurs, storytellers will inevitably take over, and the news will be downbeat. But if stocks drop to an extreme degree, as they have in the past, we can probably view it as an overreaction. That won’t help anyone’s portfolio recover any faster, but it should help us tune out the worst of the forecasters and maintain our equanimity.

How else can you maintain an even keel during a market crisis? It’s important to understand the impact of recency bias. This bias is the tendency to extrapolate from current conditions, to assume that the future will look like the present, and to downplay the possibility that things might change. That tendency is what contributed to the cycle of negative news during the depths of 2020, and this is why I think it’s so important for investors to be aware of market history.

Again, extensive analysis isn’t required. We need only look back across some of the crises the country has weathered, from the Civil War to the Depression to World War II. In each case, the economy recovered and went on to become larger and stronger than before. The lesson for investors: In the depths of a crisis, it’s very difficult to know when or how it will end. But a sense of history can help carry us through.

Those are ways to manage through a crisis. Covid also provided a lesson on how to prepare—specifically, how to prepare our portfolios—for a future downturn.

In 2022, investors were caught flat-footed when popular total-bond market funds delivered surprising losses. These funds are one pillar of the well-known three-fund portfolio and have traditionally been viewed as the default choice for a set-it-and-forget-it bond allocation. But in 2022, when the Federal Reserve hiked interest rates, these funds dropped a surprising 13%. That was during the same year that the U.S. stock market dropped nearly 20%, creating a very difficult situation for those in retirement and needing to withdraw from their portfolios.

The lesson for investors: Total-bond market funds may be well diversified, but they carry risk along another very important dimension known as duration. This is a bond metric that measures, in simple terms, how long it will take for bondholders to be repaid, and it’s a key determinant of risk. The longer the duration, the greater the risk of loss when rates rise. While total-bond market funds have holdings across a broad range of durations, they average out to nearly six years. That’s why they lost so much value in 2022.

What’s the alternative? Short-term bond funds tend to have a duration in the neighborhood of just two years. As a result, in 2022, short-term government bond funds like Vanguard’s Short-Term Treasury ETF (ticker: VGSH) lost a far more manageable 4% of their value.

To be sure, every crisis is different, and it’s easy to rationalize about the past once it’s in the past. But these lessons, I think, can help us better prepare both our emotions and our portfolios for whatever comes next.

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.