What is Dilution?

Dilution is an important concept in finance and investing, particularly for shareholders and companies issuing new shares. For a UK audience, understanding dilution is crucial for making informed decisions about investments and corporate actions.


Key Aspects of Dilution:

  1. Definition:
    • Dilution occurs when a company issues new shares, resulting in a decrease in the ownership percentage of existing shareholders. This can happen through various mechanisms such as issuing new equity, converting convertible securities, or exercising stock options.
  2. Causes of Dilution:
    • Issuing New Shares: Companies may issue new shares to raise capital for expansion, debt repayment, or other purposes.
    • Convertible Securities: Conversion of convertible bonds or preferred shares into common shares increases the total number of shares outstanding.
    • Employee Stock Options: When employees exercise stock options, new shares are created, leading to dilution.
    • Acquisitions: Companies may issue new shares to finance acquisitions, resulting in dilution for existing shareholders.
  3. Effects of Dilution:
    • Ownership Percentage: Existing shareholders own a smaller percentage of the company as more shares are added.
    • Earnings Per Share (EPS): EPS may decrease because profits are spread over a larger number of shares.
    • Voting Power: Existing shareholders’ voting power diminishes as the number of shares increases.
    • Share Value: Potential impact on the market value of shares, depending on investor perception of the reason for the new issuance.
  4. Calculating Dilution:
    • Diluted EPS: A measure that accounts for all potential dilution, calculated as:
      • Diluted EPS = (Net Income – Dividends on Preferred Shares) / (Weighted Average Shares Outstanding + Conversion of Convertible Securities + Exercise of Options)
    • Example: A company has net income of £1 million, 1 million shares outstanding, and options for 100,000 shares. If all options are exercised, diluted EPS is £1 million / (1 million + 100,000) = £0.91.
  5. Mitigating Dilution:
    • Share Buybacks: Companies can repurchase their own shares from the market to reduce the total number of outstanding shares, thereby mitigating dilution.
    • Strategic Issuance: Issuing shares for high-value projects or acquisitions that enhance the company’s value can offset the negative effects of dilution.
    • Employee Stock Option Plans (ESOPs): Managing ESOPs carefully to align with company performance and shareholder interests.
  6. Example:A UK technology firm decides to raise £5 million for expansion by issuing 500,000 new shares at £10 each. Before the issuance, the company had 1 million shares outstanding.
    • Pre-Issuance:
      • Shares Outstanding: 1 million
      • Ownership: An investor with 100,000 shares owns 10% of the company.
    • Post-Issuance:
      • Shares Outstanding: 1.5 million
      • Ownership: The same investor’s 100,000 shares now represent 6.67% of the company.

    The investor’s ownership percentage has diluted from 10% to 6.67%.


Dilution is a significant factor for both investors and companies, impacting ownership, earnings per share, and voting power. For UK investors, understanding dilution helps in making informed decisions about buying or holding shares, particularly when companies issue new equity. Companies need to manage dilution carefully to balance raising capital with maintaining shareholder value and confidence.