What Is Dilution: Share Dilution Explained

What is dilution

Dilution is the fall in an existing shareholder's percentage of ownership when a company issues new shares.

You keep the same number of shares. The total number of shares outstanding grows, so your slice of the company gets smaller. Share dilution and stock dilution mean the same thing.

A worked example (hypothetical)

Your ownership share is:

your shares ÷ total shares outstanding

Suppose a company has a fixed number of shares and you hold some of them. The company then sells a large batch of new shares to outside investors to raise cash.

The top of the fraction (your shares) stays the same.
The bottom of the fraction (total shares) gets bigger.
Your percentage of ownership, your share of voting rights and your claim on each unit of profit all fall.

If the new shares double the total share count, your ownership falls to half of what it was. The value of your holding does not have to fall. If the cash raised is used well, the company can be worth more after the issue. Dilution only describes the drop in your fraction.

The formal definition

Analysts separate two kinds of dilution:

Ownership (control) dilution. A smaller percentage of votes and of claims on assets.
Economic dilution. A lower value per share, for example lower earnings per share (EPS) or lower book value per share.

Diluted EPS is reported next to basic EPS. Basic EPS uses the shares outstanding now. Diluted EPS also counts shares that could be created later from instruments such as:

employee stock options and warrants (see call option)
convertible bonds and convertible preferred shares

The gap between basic and diluted EPS shows how much potential dilution exists.

Edge cases

Stock splits are not dilution. Every holder gets more shares in the same proportion, so ownership percentages do not change.
Rights issues. Existing holders get the right to buy new shares first. Holders who take up their rights keep their percentage. Holders who do not are diluted.
Buybacks. When a company buys back its own shares, the share count falls. This is the reverse of dilution.
Accretive issuance. Shares sold above book value per share can raise book value per share, even though each holder's percentage still falls.
Bail-ins. When debt is converted into equity in a bail-in, existing shareholders can be heavily diluted.
Crypto. People also say "dilution" when a token's supply grows through new issuance or unlocks. Here it refers to supply growth rather than ownership of a company (see altcoin).

Where you see the term

Annual and quarterly reports: "basic and diluted EPS", the weighted average share count, and notes on options and convertibles.
News: "secondary offering", "rights issue", "placement", "share-based compensation".
Platforms and stock data pages: share count, free float and corporate-action notices.

Fundamental analysts often track dilution over several years. See fundamental analysis.

If you trade share or index prices with leveraged CFDs, an issuance announcement can move the price quickly. Leveraged positions can lose money fast.

Frequent questions

What does dilution mean in simple words?

The company creates new shares, so each existing share stands for a smaller part of the company.

Does dilution always lower the share price?

No. The price depends on what the company does with the money it raises and how the market judges that. Dilution itself only describes the lower ownership percentage.

What is the difference between basic and diluted EPS?

Basic EPS divides profit by the shares outstanding now. Diluted EPS also includes shares that options, warrants and convertibles could add later.

Is a stock split dilution?

No. Every holder's proportion stays the same.

How can an existing shareholder avoid being diluted?

In a rights issue, a holder who buys their allotted new shares keeps the same percentage. In other types of issuance, existing holders usually cannot prevent dilution.