How Diversified Has Berkshire’s Portfolio Really Been?

 

When people think of Warren Buffett, they often imagine a carefully diversified portfolio. The truth? Berkshire’s equity bets having minority interest ,have usually been highly concentrated. Here’s how the story unfolds decade by decade:

1960s – Early Bets, Big Swings
In the Buffett Partnership years, a handful of stocks made up most of the portfolio. At one point, American Express alone was over 40%. After taking control of Berkshire in 1965, he continued running with fewer than 10 serious holdings.

1970s – The Media Era
Buffett bought Washington Post (a quarter of the portfolio at one stage) and GEICO. He stuck to media and financials. The idea of “owning just the best” shaped his investing.

1980s – Coca-Cola Takes Over
The 1988 Coca-Cola purchase was a game changer — it quickly became 30–40% of the portfolio. Alongside GEICO, Gillette, and Wells Fargo, Buffett doubled down on household names.

1990s – Four Giants Rule
By the late 90s, just four stocks (Coca-Cola, American Express, Gillette, Wells Fargo) made up over 70% of the portfolio. Buffett’s mantra: “Diversification is protection against ignorance.”

2000s – Some Broadening, Still Top-Heavy
Berkshire added Moody’s, PetroChina, Johnson & Johnson, energy, and industrials. Yet the old favorites — Coke, Amex, Wells Fargo, Moody’s — stayed dominant.

2010s – Apple Becomes the New Coke
The Apple bet after 2016 changed everything. It grew into more than 40% of Berkshire’s holdings. With Todd Combs and Ted Weschler managing smaller positions (Amazon, Snowflake, biotech), the portfolio had more names — but still very lopsided.

2020s – Apple being shed but still dominant
Berkshire has been selling Apple gradually but still remains its largest minority owned holding. 

Bottom line: Buffett has never believed in spreading bets too thin. His approach has always been about a few big, conviction plays — not traditional diversification.