# How to Build a Diversified Portfolio

> You build a diversified portfolio by spreading money across ~20–30 stocks, multiple sectors, and different company types, so no single holding or industry can sink your returns — reducing company-specific risk while keeping market exposure.

## Why diversification works

Every stock carries systematic risk (the market falling) and unsystematic risk (company-specific events). Diversification can't remove market risk but nearly eliminates company-specific risk — the only free lunch in investing.

## How many stocks?

Most company-specific risk is diversified away by ~20–30 well-chosen stocks across sectors. Beyond ~30 adds little; fewer than 10 leaves you exposed. Quality of diversification beats raw count.

## Diversify across sectors

| Type | Examples | Behavior |
|------|----------|----------|
| Defensive | Staples, utilities, healthcare | Steadier in downturns |
| Cyclical | Industrials, materials, discretionary | Swing with the economy |
| Growth | Tech, communications | Higher upside/volatility |
| Income | REITs, dividend payers, financials | Yield and ballast |

A portfolio tracker (/portfolio-analytics) makes concentration visible.

## Beyond sectors

- **Size** — mix large, mid, small caps.
- **Geography** — US, Canada, UK exposure.
- **Style** — blend value and growth (/blog/value-investing-vs-growth-investing).

## Rebalancing

Winners grow oversized and raise risk. Rebalance once or twice a year to restore targets and enforce sell-high/buy-low.

## Quality first

Diversifying across 30 weak companies just guarantees mediocrity. Vet holdings with fundamental analysis, then diversify against the unknowns.

## FAQ

**How many stocks should I own?** For most investors, 20–30 stocks spread across different sectors captures nearly all the benefit of diversification. Fewer leaves you exposed to single-company risk; many more adds tracking effort without much extra protection.

**Can you be too diversified?** Yes. Owning too many stocks (over-diversification, or 'diworsification') dilutes your best ideas and can drag returns toward a plain index fund while costing more effort. Aim for enough holdings to spread risk, not so many you can't follow them.

**Does diversification reduce returns?** Not necessarily. It reduces company-specific risk without lowering expected market return. It does cap the upside of any single winner, but it also protects you from any single disaster.

## Related reading

- Portfolio Analytics (/portfolio-analytics)
- Value vs. Growth Investing (/blog/value-investing-vs-growth-investing)
- Dividend Investing Guide (/learn/dividend-investing-guide)

Track your portfolio free: https://foliofundamentals.com/portfolio-analytics