Are You Too Diversified To Win?

QUESTION: Stocks are hitting new highs again despite the war with Iran and higher oil prices. Am I missing out by being too diversified?

ANSWER: A prudent advisor usually preaches diversification—and for good reason. It can deliver stock-like returns while reducing the risk tied to any single investment. That’s a pretty good deal. However, it’s possible to think you’re well diversified when you’re not. It’s also possible to overdiversify.

Looking diversified when you’re not: Many investors assume diversification simply means owning many stocks. But if those stocks are closely related, you may not be diversified at all. The S&P 500 is a good example. Owning 500 companies sounds diversified, but the index has become heavily concentrated in a relatively small group of large technology companies tied to artificial intelligence (AI) and the infrastructure that supports it.

Roughly 40% of the S&P 500’s value is tied to companies benefiting from the AI infrastructure boom. Those returns have been phenomenal in recent years. But if those companies stumble, the S&P 500 will likely stumble, too. That doesn’t mean investors should avoid the index. It means they should understand where their risks are concentrated and consider balancing that exposure with investments driven by different economic factors.

Overdiversifying: The opposite problem is owning too many stocks.

Diversification reduces risk, but beyond a certain point, adding more stocks provides diminishing benefits. Why? Because a portfolio manager can only have so many “best ideas.” If a manager owns 1,000 stocks, the big winners aren’t a large enough percentage to make a meaningful contribution. Eventually, the portfolio begins to resemble an index fund, but often with higher costs.

So, are you missing out? Investors posting outsized returns today may simply be taking more risk than they realize. Much of that risk is hidden because it comes from concentration in a single theme, such as artificial intelligence. If the AI story keeps delivering, those investors may continue to outperform. If it doesn’t, they may get a firsthand lesson in the dangers of concentration.

Diversification isn’t as exciting as AI. It often means owning investments that are boring. But over time, diversification remains one of the most reliable ways to participate in market growth while avoiding the potentially devastating impact of having too much riding on a single idea.