Stock (Share)

A stock is a slice of ownership in a company; holders share in its profits and losses.

Why investors care

It is the building block of nearly every portfolio.

Where people go wrong

Owning one share makes you a part-owner, but with no say in daily operations.

In the real market

In 2008, a broad stock index fell 37% in a year — a brutal loss that emptied the stomachs of millions of investors. Those who sold at the bottom locked in the loss permanently. Those who held, and kept contributing, saw the same index triple over the following decade. The scenario is the fundamental bargain of stock ownership: you absorb violent drawdowns in exchange for the growth of the whole economy, and the bargain only works if you can hold through the pain.

Using it in practice

Own stocks through a diversified fund for the core of your portfolio, and treat individual picks as satellites. Match your stock weight to your horizon and tolerance, because equities can drop 30–50% in bad cycles and still reward those who hold.

Example in numbers

Key takeaway

A stock is a slice of ownership with a residual claim — paid last, wiped out first, and entitled to all the growth beyond what lenders are owed. That position in the capital structure is why equities earn a risk premium and why they are the highest-returning major asset class over long horizons. Own them through diversified funds for the core of a portfolio and match the weight to your horizon, because equities can drop 30–50% in bad cycles. The risk is real; the long-run reward is the compensation for it.

Definitions reviewed by the Investing Glossary editorial team.