"How many stocks should I hold?" is one of the most common questions in investing — and the honest answer is a range, not a magic number. You want enough names to be diversified, but few enough to stay disciplined and actually follow them. Here is how to think about it, and the simple maths underneath. This is for learning only.
Why too few is a gamble
Hold three or four stocks and you are not really investing in the market — you are making a handful of concentrated bets. One earnings miss, one governance scandal or one bad sector can wreck the whole portfolio. Even famous, "safe" names have fallen 80–95% and never recovered. If your savings sit in one such stock, there is no second basket to catch you.
Why too many is also a mistake
Pile in 80 or 100 names and you get the opposite problem. Your best ideas get diluted into insignificance, you cannot realistically follow that many businesses, and you have quietly built an expensive index fund by hand — at more cost and effort than simply buying an index.
The maths of the sweet spot
Decades of research point to the same place. Diversification works by removing company-specific risk — the danger that one firm's bad news sinks you. That risk falls sharply as you add the first several stocks, and most of the benefit is captured by roughly 20 to 30 well-spread names. Beyond that, each extra stock removes very little further risk; you add complexity for almost no reward.
What diversification can never remove is market risk — the whole market falling together. No number of stocks protects you from that, which is another reason piling on a 60th name is mostly just extra work.
Size matters as much as count
The number of stocks is only half the job. The other half is the size of each position:
- A common guideline: no single stock more than about 3–8% of the portfolio.
- Spread across different sectors and market sizes, so one bad industry can't take everything down.
The arithmetic is the whole point: if a position is about 3% of your portfolio and that stock falls 50%, your total portfolio only feels about 1.5%. Small, sensible position sizes are what let you survive the inevitable mistakes. We cover this in detail in what position sizing is.
"Thirty in one sector" is not diversified
Thirty stocks all in banking is not a diversified portfolio — it is one big bet on banks. What protects you is the spread: different companies, different sectors, different market-cap sizes, so a shock to one corner of the market doesn't take the whole book with it.
Let the count follow the rules
In a rule-based model you don't pick the number — the rules do. Names enter when they qualify and leave when they don't, and the portfolio naturally settles at or below its cap. Our Model Portfolio is capped at 30 positions, each roughly equal-weighted at about 3% of capital and spread across sectors — diversification as a by-product of discipline, not a target managed by hand. See the methodology for exactly how, and create a free account to follow the closed track record.
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