Key Points
- Diluted EPS includes only instruments that reduce earnings per share; anti-dilutive instruments are excluded from the calculation.
- IAS 33.36 requires the entity to use the treasury stock method for share options and warrants, assuming proceeds are used to buy back shares at the average market price.
- Entities listed on a regulated European market must present both basic and diluted EPS on the face of the statement of profit or loss, not buried in the notes.
- Omitting a dilutive instrument or applying the wrong sequencing can overstate diluted EPS and mislead investors about potential dilution.
What is Earnings per Share (Diluted)?
IAS 33.30 defines diluted EPS as earnings per share (basic) recalculated on the assumption that all dilutive potential ordinary shares outstanding during the period were converted. The calculation adjusts both the numerator (profit attributable to ordinary shareholders) and the denominator (weighted average number of ordinary shares).
For convertible instruments such as convertible bonds, IAS 33.33 requires the numerator to add back the after-tax interest expense that would have been avoided if conversion had occurred. The denominator adds the shares that would have been issued on conversion. For share options and warrants, IAS 33.45 applies the treasury stock method: the calculation assumes the options are exercised at the start of the period (or grant date, if later), and the proceeds the entity would receive are treated as if used to repurchase shares at the average market price. Only the incremental shares (those exceeding the notional buyback) enter the denominator.
IAS 33.41–44 requires the entity to test each potentially dilutive instrument individually, then rank them from most dilutive to least dilutive. The entity includes instruments one at a time in this sequence and stops when the next instrument would be anti-dilutive. This sequencing rule prevents an anti-dilutive instrument from masking the dilutive effect of others. The auditor applies ISA 540.13(a) to evaluate whether the entity's method is appropriate, focusing on the completeness of the population of potential ordinary shares, the accuracy of the exercise prices used, and the correct application of the sequencing test.
Worked example: Schäfer Elektrotechnik AG
Client: German electronics company, FY2025, revenue €310M, IFRS reporter listed on the Frankfurt Stock Exchange. Schäfer reports net profit attributable to ordinary shareholders of €18.6M. The weighted average number of ordinary shares outstanding during FY2025 is 12,000,000. Schäfer has two potentially dilutive instruments: (a) 600,000 share options granted to senior management with an exercise price of €24 each, and (b) €10M in convertible bonds carrying 3% annual interest, convertible into 800,000 ordinary shares. The average market price of Schäfer's shares during FY2025 is €40. The corporate tax rate is 30%.
Step 1 — Calculate basic EPS
Net profit of €18.6M divided by 12,000,000 shares produces basic EPS of €1.55.
Step 2 — Apply the treasury stock method to the share options
The 600,000 options at an exercise price of €24 would generate notional proceeds of €14.4M. At the average market price of €40, the entity could notionally repurchase 360,000 shares (€14.4M divided by €40). The incremental shares added to the denominator are 600,000 minus 360,000, giving 240,000 shares. No numerator adjustment arises for options under the treasury stock method.
Step 3 — Adjust for the convertible bonds
If converted, the entity avoids annual interest of €300,000 (3% of €10M). The after-tax saving is €210,000 (€300,000 multiplied by (1 minus 0.30)). The denominator increases by 800,000 shares.
Step 4 — Rank instruments and calculate diluted EPS
The share options produce an incremental EPS effect of nil on the numerator and 240,000 on the denominator. The convertible bonds produce €210,000 on the numerator and 800,000 on the denominator, giving an incremental EPS of €0.2625 per incremental share. The options are more dilutive (lower incremental EPS per share), so they enter first.
After including options: EPS = €18.6M / 12,240,000 = €1.5196.
After including convertible bonds: EPS = (€18.6M + €0.21M) / 13,040,000 = €1.4432.
The convertible bonds remain dilutive (€1.4432 is below €1.5196), so both instruments are included. Diluted EPS is €1.44 (rounded to two decimal places).
Conclusion: diluted EPS of €1.44 is defensible because both instruments pass the dilution test in the correct sequence, the treasury stock method uses a verifiable average market price, and the convertible bond adjustment reflects the actual after-tax interest saving.
Why it matters in practice
Teams frequently include all potential ordinary shares in the diluted EPS denominator without performing the IAS 33.41–44 sequencing test. When instruments are included in the wrong order (or all at once), anti-dilutive instruments can slip into the calculation and understate diluted EPS. ISA 540.13(a) requires the auditor to evaluate whether the method is appropriate, and skipping the sequencing step fails that requirement.
The treasury stock method under IAS 33.45 requires use of the average market price for the period, not the closing price at year-end. Using the year-end closing price produces the wrong number of notional shares repurchased and distorts the incremental share count. The error is more material in volatile share price environments where the average and closing prices diverge significantly.
Diluted EPS vs. basic EPS
| Dimension | Basic EPS (IAS 33) | Diluted EPS (IAS 33) |
|---|---|---|
| Denominator | Weighted average ordinary shares actually outstanding | Weighted average shares plus incremental shares from dilutive potential ordinary shares |
| Numerator | Profit attributable to ordinary shareholders | Profit adjusted for after-tax effects of assumed conversion (e.g., convertible bond interest added back) |
| Options and warrants | Ignored | Included via treasury stock method if dilutive |
| Presentation | Face of the statement of profit or loss (IAS 33.66) | Presented with equal prominence alongside basic EPS (IAS 33.66) |
| Purpose | Shows actual earnings allocation to existing shareholders | Shows maximum potential dilution if all dilutive instruments converted |
The distinction matters when an entity has issued convertible instruments or share-based payments. A large gap between basic and diluted EPS signals that existing shareholders face material dilution risk, and investors use the spread to assess future equity dilution before committing capital.
Related terms
Frequently asked questions
How do I document diluted EPS in the audit file?
List every potential ordinary share outstanding at the reporting date (options, warrants, convertibles, contingently issuable shares), record the terms of each instrument, and document the sequencing test from most dilutive to least dilutive. IAS 33.70(b) requires disclosure of instruments that could dilute EPS in the future but were excluded as anti-dilutive in the current period. The audit file should mirror that disclosure with the supporting calculations.
Does diluted EPS apply to interim financial statements?
Yes. IAS 33.4 requires entities that present earnings per share under IAS 33 to calculate diluted EPS for every period for which a statement of profit or loss is presented, including interim periods reported under IAS 34. The weighted average share count and the average market price for the treasury stock method are calculated for the interim period, not annualised from the full year.
What happens to diluted EPS when all options are out of the money?
When the exercise price of share options exceeds the average market price for the period, the treasury stock method produces a negative incremental share count (the notional buyback exceeds the shares issued). IAS 33.47 treats these options as anti-dilutive, and the entity excludes them from the diluted EPS calculation entirely. Diluted EPS equals basic EPS in this scenario if no other dilutive instruments exist.