Earnings Per Share
Basic earnings per share represents the amount of income attributable to each common share outstanding. Diluted earnings per share represents the amount of income attributable to each common share outstanding adjusted for the effects of potentially dilutive common shares. Potentially dilutive common shares include stock options and other stock-based awards. In the periods where the effect would be antidilutive, potentially dilutive common shares are excluded from the calculation of diluted earnings per share.
In periods in which the Company has net income, earnings per share is calculated using the two-class method. This method is required as unvested pre-IPO restricted stock awards have the right to receive non-forfeitable dividends or dividend equivalents if the Company were to declare dividends on its common stock. Pursuant to the two-class method, earnings for each period are allocated on a pro-rata basis to common stockholders and unvested pre-IPO restricted stock awards. Diluted earnings per share is computed using the more dilutive of (a) the two-class method, or (b) treasury stock method, as applicable, to the potentially dilutive instruments.
Our basic and diluted earnings per common share are calculated as follows:
Year Ended December 31,
in thousands of U.S. dollars and share amounts (except per share amounts)202520242023
Earnings:
Net income $77,949 $44,398 $51,376 
Less: Allocation to participating securities4 59 287 
Net income attributable to Sotera Health Company common stockholders$77,945 $44,339 $51,089 
Weighted Average Common Shares:
Weighted-average common shares outstanding - basic283,956 282,784 281,008 
Dilutive effect of potential common shares2,465 2,122 2,213 
Weighted-average common shares outstanding - diluted286,421 284,906 283,222 
Earnings per Common Share:
Net income per common share attributable to Sotera Health Company common stockholders - basic$0.27 $0.16 $0.18 
Net income per common share attributable to Sotera Health Company common stockholders - diluted0.27 0.16 0.18 
Diluted earnings per shares does not consider the following potential common shares as the effect would be anti-dilutive:
Year Ended December 31,
in thousands of share amounts202520242023
RSUs9 34 291 
Stock options5,550 5,469 4,108 
Total anti-dilutive securities5,559 5,503 4,399 

About Earnings Per Share Disclosures

The earnings per share disclosure breaks down the calculation from net income to both basic and diluted EPS, revealing the full impact of a company's capital structure on per-share economics. The reconciliation between basic and diluted share counts exposes how many stock options, RSUs, convertible securities, and warrants are potentially dilutive to existing shareholders.

Key signals: a widening gap between basic and diluted shares indicates growing dilution from equity compensation or convertible instruments. Anti-dilutive securities excluded from the diluted calculation deserve attention — they represent latent dilution that will materialize if the stock price rises. Watch for the effect of share buybacks on per-share metrics: EPS growth driven primarily by repurchases rather than income growth signals weakening fundamentals. Compare year-over-year changes in the diluted share count against equity compensation expense to assess whether management is effectively managing dilution.