Strategy

Here's How To Do Warren Buffett's Favorite Critical Thinking Exercise

King and Warren Buffett
Warren Buffett wins the trophy for critical thinking. Here's one way he does his training. REUTERS/Jo Yong-Hak
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The Sage of Omaha has a ridiculously fit mind — anything he says becomes news.  

While Buffett's brain is constantly working to crank through books, play bridge, and lobby Congress, the man is also deliberate about doing mental weightlifting. 

Bill Gates — a close friend of the investor — recounted in 1996 Fortune column an exercise Buffett liked to do in critical thinking.

It's part of how their friendship started.

"On that first day, [Buffett] introduced me to an intriguing analytic exercise that he does," Gates said. "He'll choose a year — say, 1970 — and examine the 10 highest market-capitalization companies from around then. Then he'll go forward to 1990 and look at how those companies fared. His enthusiasm for the exercise was contagious."

Pretty cool, right? With this exercise, you can practice spotting trends, analyze why some companies sustain success while others slip, and how technology advances and cultural norms shape business.

We did a version of this exercise, comparing the market leaders over a 20-year interval. We looked at 1990 and 2010, using information provided to us by Howard Silverblatt, a senior index analyst at S&P Dow Jones Indices

Here are the 10 largest market-cap companies of 1990: 

1. IBM ($64.53 billion)
2. Exxon ($64.49 billion)
3. GE ($50.34 billion)
4. Philip Morris ($47.89 billion)
5. Royal Dutch Petrol ($42.15 billion)
6. Bristol-Myers Squibb ($35.2 billion)
7. Merck & Co ($34.81 billion)
8. Wal-Mart Stores ($34.26 billion)
9. AT&T ($32.8 billion)
10. Coca-Cola ($31.05 billion)

And the 10 largest market-cap companies of 2010: 

1. Exxon Mobil ($368.71 billion)
2. Apple Inc. ($295.89 billion)
3. Microsoft ($238.79 billion)
4. Berkshire Hathaway ($198.03 billion)
5. GE ($194.88 billion)
6. Wal-Mart Stores ($192.1 billion)
7. Google ($189.94 billion)
8. Chevron ($183.64 billion)
9. IBM ($182.32 billion)
10. Procter & Gamble ($180.07 billion)

Summoning our inner Buffett, let's look at the overall shifts. Four companies — IBM, Exxon, GE, and Wal-Mart — stayed on top, while six fell off. Over the same period, several new entrants — Apple, Google, and Microsoft — claimed top spots. 

There are a few takeaways.

First, changes in culture can lay waste to a consumer goods empire. Tobacco maker Philip Morris was gigantic back in 1990 when smoking was a popular habit, but legislation has deeply cut into its business. California rolled out the first smoking ban in 1995, starting a state-by-state trend that's curbed Philip Morris' dominance. And having all those Marlboro Men die of smoking-related diseases didn't help much, either. 

Second, major corporations can sustain themselves if they stay "agile," as management experts like to say. GE has been so innovative for so long that it's shaped a lot of modern life. Thomas Edison's company kept it up into the new century, coming out with medical breakthroughs like high-definition brain scans and cancer detection devices. And while IBM slipped from its No. 1 rank as the world's most valuable company in 1990, the computing behemoth successfully moved into China and other emerging markets, and hopped onto massive trends in tech like cloud computing, bringing in billions in revenue

Third, monopolistic companies can stay dominant if their market stays stable. Wal-Mart has presided over American low-cost retail for decades now, and the company shows no signs of slipping. Like billionaire investor Peter Thiel says, the monopoly is the finest form of capitalism.

If you have more observations, tell us in the comments. 

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Drake Baer was Business Insider's editor-at-large, working across the newsroom to help produce ambitious journalism. For two and a half years before that, Baer served as deputy editor, overseeing a team of 20+ reporters and editors who cover the future of work, real estate, and small business. The fast-paced team was behind some of Insider's major packages in the last few years, including a state-by-state look into unemployment during the first year of the pandemic and in-depth profiles of "niche famous" characters such as real estate media tycoon Brandon Turner and HR icon Johnny C Taylor. They shed new light on big names, like Joe Biden, America's imperfect leader. He also cultivated thesis-oriented ideas journalism, whether it be on why "'diversity' and 'inclusion' are the emptiest words in corporate America" or why it's actually a horrible time to buy a house. (No, really, it is.) Before editing, his byline as a reporter was on the masthead for Fast Company and New York Magazine, covering the many intersections of social science, business, and economics. Baer has interviewed some our time's leading minds, including philanthropist Bill Gates, FiveThirtyEight founder Nate Silver, NBA champion and investor Steph Curry, "growth mindset" psychologist Carol Dweck, the rapper Q-Tip, Nobel laureate Daniel Kahneman, and the man who gave a name to "disruptive innovation," the late Clay Christensen.Baer has published two books, the most recent being Perception: How Our Bodies Shape Our Minds, with Dennis Proffitt. In 2014, New York Times bestselling author and Wharton professor Adam Grant highlighted his first book, Everything Connects, as one of the 12 business books to read that year. He has been featured as a speaker at the Aspen Ideas Festival, presented at TedX Princeton, and moderated many panels.