How big is too big?
As of last month, the Magnificent Seven stocks (Apple, Microsoft, Alphabet, Amazon, Nvidia, Meta, and Tesla) represent around 34% of the S&P 500 index’s total market capitalization.
In other words, a mere seven stocks now account for more than a third of the entire market.
Many investors see this level of concentration and — understandably — expect things to end badly.
But this week’s chart suggests that their fear might be misplaced.
Big Concentration Is Nothing New
Our chart this week comes from A16Z. It tracks the share of the largest sector in the U.S. stock market over more than 200 years.
It’s shocking when you realize how much larger the previous leaders were.
Finance and real estate were nearly the entire market in the early 1800s. Railroads and transport climbed to roughly 70% of market value in the late 19th century. And energy and materials had their own long stretches of oversized dominance.
By comparison, even after the current run in AI-related stocks, technology still sits well below many of those historic peaks.
The popular narrative today is that the Mag 7 concentration is unprecedented.
But history says otherwise.
In fact, concentration around breakthrough technologies is perfectly normal. That’s because money tends to pile into platforms with the power to reshape the economy.
It happened with railroads, with electrification and with computing.
And it’s happening today with AI.
But what I find even more interesting is what happens after these periods of dominance.
Railroads didn’t fade into irrelevance when their share of the market declined. They simply became infrastructure.
By this I mean they helped create an economy much larger than the railroads themselves. They gave rise to industrial giants and national supply chains, and they enabled forms of wealth creation that were hard to imagine before railroads existed.
That’s what’s easy to miss with today’s AI buildout.
The leading technology of an era doesn’t just create winners inside its own category. It often creates entirely new categories of opportunities.
In fact, nearly 70% of today’s market is made up of industries that were tiny or even nonexistent in 1900.
That means the real opportunity in AI today might not be with its current leaders.
It could come from what AI makes possible next.
Autonomous systems, robotics infrastructure and synthetic biology are just some examples of entirely new industries taking shape because of AI.
Yet, they could be where the biggest opportunities emerge.
That’s why I’m less concerned with technology’s market dominance today than I am with whether investors are underestimating what comes next.
Here’s My Take
Some investors see AI’s growing share of the market as a dangerous thing.
And they could be right if it’s merely speculation.
But as this week’s chart shows, concentration often happens when the market recognizes a new foundation being built.
And history tells us that dominant technologies often expand the economic pie.
Railroads didn’t end with railroads. The internet didn’t end with software. And I doubt AI ends with today’s model builders.
In fact, as AI becomes a foundational intelligence layer across the economy, today’s concentration might someday look like the opening chapter of something much bigger.
So how big is too big?
To me, the bigger risk is underestimating just how large this opportunity could become.
Regards,
Ian KingChief Strategist, Banyan Hill Publishing
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