What Is Diversification?

Diversification spreads money across different investments, such as companies, industries, asset types, or regions, so no single one has an outsized effect on your overall results.

The basic logic

Put all your money in one company's stock, and that company's struggles become your struggles. Spread your money across dozens or hundreds of companies, and one company doing poorly barely moves the total, especially while others do well at the same time.

The levels of diversification

• Within an asset type. Own many stocks instead of one, or many bonds instead of one.
• Across asset types. Hold a mix of stocks, bonds, and other assets that do not all move the same direction at the same time.
• Across regions. Avoid concentrating entirely in one country's economy.

An index fund gives you broad diversification within an asset type through a single investment, instead of buying many individual holdings yourself.

What diversification cannot do

Diversification reduces the risk tied to any single company or investment failing. It does not eliminate risk overall. A widely diversified portfolio still loses value, especially in the short term or during a broad market downturn that hits most investments at once. It does not guarantee a profit either.

The link to time horizon

Diversified money still needs time to ride out short-term swings. Money you need soon gets handled differently than money with a long runway. See investing basics for that distinction.

Nothing here recommends a specific level or method of diversification for your situation. That depends on your goals, timeline, and risk tolerance.