David Booth Built a $1 Trillion Firm by Not Predicting Markets. His Advice Now — BigGo Finance

In March 2020, as COVID-19 cases spread and US stocks plunged roughly 30%, David Booth did not reach for a model or a trading terminal. He did not predict a V-shaped recovery or a lost decade. What he did, he says, was remind himself of a simple fact: people would not just sit there and take it. They would figure out how to get back on track.

The recession lasted one quarter.

There is a version of the investing world where that sounds like naive optimism. Booth, the founder and chairman of Dimensional Fund Advisors, the $1 trillion asset manager he started from his Brooklyn apartment in 1981, has spent 45 years insisting it is something else: realism. On the podcast Top Traders Unplugged, he laid out the case that investors waste enormous energy trying to predict markets when they could instead be learning to manage uncertainty—and that the difference explains why some investors capture the market’s full long-term return while others fall short.

From Kansas to the Birth of Index Investing

Booth’s intellectual roots go back to the University of Chicago in the late 1960s, a place he describes as electric with new discoveries. For the first time, researchers had quality data and powerful computers, which allowed them to test claims about investing that had previously been accepted on faith. Many of those claims did not survive scrutiny.

The counterintuitive finding: professional money managers could not reliably beat the market. The more useful question, Booth realized, was not “how do we outguess the market?” but “how do we beat the market without trying to outguess it?”

He left his PhD program in Chicago—he says he told Gene Fama, the future Nobel laureate, that he was not cut out for academic research—and went to Wells Fargo in San Francisco. There he worked alongside Fischer Black and Myron Scholes, two young assistant professors who would later develop the Black-Scholes option pricing model. They pursued a science-driven approach to portfolio construction.

Booth is careful to distinguish this from the index fund concept, which he says did not come from the scientists. It came from Wells Fargo’s marketing department. “I don’t think the scientists were led to that. I think it’s people from the marketing group there that realized that’s a pretty easy concept to sell. You know, look, what we can do is track an index for you.”

Both approaches proved commercially viable. Indexing now captures roughly half of equity mutual fund assets. But Booth’s group disbanded when Wells Fargo lost interest, and in 1981 they reconvened to form Dimensional. The firm’s first product was a small-cap portfolio—Booth claims Dimensional was the first to use “small cap” as an investment category. When he applied for six telephone lines for his Brooklyn apartment office, New York Telephone refused, suspecting a bookmaking operation. He had to appeal to an assistant treasurer to get the lines installed.

Uncertainty Is the Product, Not the Problem

Booth’s central argument in his new book, Stay Calm: Learn to Embrace Uncertainty in Investing and in Life, is that uncertainty is not a bug in the financial system. It is the commodity that investors are buying.

“Uncertainty creates the opportunity,” he said. “Suppose there were no uncertainty, everything was pre-ordained. Life would be pretty dull and it would take away the possibility of actually progressing.”

The practical implication is that investors should stop trying to eliminate uncertainty and start managing it. The levers are straightforward: control how much risk you take through your allocation between stocks and riskless assets, and diversify so that no single stock’s failure can destroy your portfolio. Individual stocks can go to zero. The stock market cannot.

This reframing has roots in Booth’s reading of market history. Over the last hundred years—through the Great Depression, World War II, high inflation, and every other stress test—US stocks have returned about 10% per year. His explanation is not financial engineering but human nature: people want to make their lives better, and firms want to improve.

Kevin Cold Iron, the host, put it plainly about the COVID recovery: “That’s human ingenuity. That’s actually what happened… It shows you how amazing the economy is and the people in it.”

The Discipline of Planning Without Predicting

Booth’s book title is a philosophy wrapped in a command: stay calm. His framework for doing that has several core principles.

First, plan, do not predict. You cannot know where you will be in 20 years, so do not pretend otherwise. Build a thoughtful plan based on your circumstances and stick to it. Second, control what you can control—which is not the market, but your risk exposure and diversification. Third, meaningful changes to your portfolio should come from your life, not the news cycle. Retirement, children, buying a house: these are legitimate triggers for adjusting your approach. A volatile week in the S&P 500 is not.

Booth also draws an analogy to medicine to explain why professional advice matters. People see doctors for serious medical issues. But everyone has a serious financial issue regardless of their wealth. Advisors, he argues, create distance between the investor and the portfolio, reducing the emotional damage investors can inflict on themselves. Research from behavioral economists supports this: people with advisors tend to do better and be happier, not necessarily because advisors have superior skill, but because they prevent impulsive mistakes.

Indexing’s Secret: People Use It to Time Markets

One of the podcast’s sharpest observations is about indexing itself. With roughly half the market now in index funds, one might expect a corresponding decline in trading activity. The opposite has happened. Trading volume has exploded.

Booth’s explanation: “Indexing is the ideal way to time markets because you can buy a whole market very inexpensively and get in and get out.”

Investors have given up on stock picking, but they have not given up on market timing. They have simply switched tools. This is a critical distinction for anyone who believes that the rise of passive investing has made the market less efficiently priced. Booth argues the opposite: the market remains efficiently priced because sophisticated institutional investors sit on both sides of every trade, correcting any deviation from fair value almost instantly. The competition that drives fair pricing is intact.

Booth also addressed the question of whether indexing has changed the market itself. He draws a sharp line between indexing and the science-driven approach he built Dimensional on. Index funds, he explains, give up flexibility. When an index provider changes constituents, index funds must buy and sell at the same time as everyone else. The science-driven approach uses flexibility to structure portfolios better, to trade better, and to pay attention to details.

This flexibility has economic value, Booth insists. That is why Dimensional has thrived even as index fees collapsed. “Ideas are cheap,” he said. “It’s execution that counts.”

The Outsider Mindset and the Small-Cap Test

Dimensional’s origin as a small-cap specialist provides a case study in how to handle evidence that does not always cooperate. Booth was candid about the firm’s track record: “Our first nine years, when all we had was really a small cap portfolio, it performed miserably. You know, the last 35 years it’s done fine. The last 10 not so well.”

The timeline is important. An investor who evaluated Dimensional’s small-cap approach after nine years would have concluded it was a failure. An investor who waited 35 years would have seen a different picture. An investor looking at the last ten years would be underwhelmed again. The lesson is not that small caps are good or bad, but that you have to look at strategies over decades, not years.

Booth also clarified a common misunderstanding about Dimensional’s original thesis. It was not that small caps would outperform. It was that investors should hold both large and small company stocks. In 1981, institutional investors did not meaningfully invest in small companies at all. Dimensional’s breakthrough was creating the category.

That willingness to challenge assumptions is what Booth means when he calls himself an outsider—a striking self-description for the founder of a $1 trillion firm. “I come from a background of outsiders, and I think you always want to be an outsider and challenge what the insiders are doing.”

He tells his current portfolio managers how he managed portfolios 45 years ago, and they howl at his naivety. His response: “In 40 years, whoever runs the portfolios will laugh at them too. The research is never finished.”

Tuning Out the Noise

One of Booth’s most practical ideas is his distinction between data and meaningful information. He argues that “interesting” is not the same as “meaningful.” The volume of data available today is unprecedented, but most of it does not warrant action.

His personal checklist for evaluating new information: go back to first principles—is there an economic principle here?—and ask whether the information has any evidence to suggest it is meaningful to your portfolio. If it is interesting but not actionable, let it go. Only make changes based on meaningful information, which typically comes from your own life circumstances, not market events.

Booth collaborated with filmmaker Errol Morris on a short film called Tune Out the Noise to explore this theme. The discipline is not about ignoring the world, but about sorting signal from noise efficiently. With AI increasing the volume of available content, he expects this skill to become even more valuable.

Optimism as a Data-Driven Position

Booth’s book concludes with a chapter titled “Why I Will Always Be Optimistic About the Future,” but he refines this in conversation: he calls himself a realist, not an optimist. The distinction matters. An optimist can be hopeful without data. A realist uses data to ensure that whatever they do is grounded in reality.

The data, in this case, is the market’s long-term record and the structural competition that drives pricing. A trade only happens when both buyer and seller believe they are getting a good deal. That competitive tension leads to good outcomes—not because people are nice, but because they are competing.

When asked why he would rather be an investor today than when he started in 1971, Booth’s answer is practical. Fees are dramatically lower. Portfolios are better diversified. Risk controls are better. The net return—return minus fees—is higher for the same exposure. The basic truth that it is tough to beat the market was true then and remains true now, but the cost of participating has fallen dramatically.

That is the final synthesis of Booth’s message: accept that you cannot predict markets, accept that uncertainty is the source of returns, accept that there are no optimal solutions—only tradeoffs—and accept that the market’s long-term performance is not a promise but a probability. Sometimes you get a bad draw. That is what uncertainty means. The response is not to predict harder, but to stay calm, stay diversified, and let the market work for you.