Diversification

What Is Diversification?

Diversification is the practice of spreading investments across a variety of holdings instead of concentrating money in a single company, industry, or type of asset. The basic idea is that different investments do not always rise and fall at the same time. When one part of a portfolio performs badly, another part may hold steady or even gain, which can soften the overall impact on the portfolio's value.

Diversification does not guarantee a profit or protect against all losses. Broad market declines, sometimes called systematic risk, can affect most investments at once. Diversification is mainly aimed at reducing unsystematic risk, which is the risk tied to a specific company or sector.

How Diversification Works

Investors can diversify in several ways:

• Across asset classes, such as stocks, bonds, and cash equivalents
• Across industries, so that a downturn in one sector does not dominate results
• Across company sizes and styles, such as large-cap and small-cap firms
• Across countries and regions, which reduces dependence on one economy
• Within a single fund, since a broad index fund can hold hundreds of companies at once

The degree to which diversification helps depends on how closely the holdings move together. This relationship is often measured by correlation. Assets with low or negative correlation tend to offer more diversification benefit than assets that move in lockstep.

Why It Matters to Investors

Diversification is widely discussed as a way to manage risk relative to return. A portfolio concentrated in one stock can gain sharply or lose heavily, while a diversified portfolio usually experiences smaller swings. The tradeoff is that diversification also limits the upside of any single winning investment. A holding that performs exceptionally well may matter less to total returns when it is only one small part of a larger portfolio.

Investors also need to watch for hidden overlap. Owning several funds that all track the same index or hold the same large companies may create less diversification than the number of holdings suggests. Reviewing the underlying holdings and how the parts of a portfolio relate to one another is one way to check whether diversification is working as intended.