EARNINGS PER SHARE
The Company presents both basic and diluted earnings per share of common stock (EPS) amounts. Basic EPS is calculated by dividing net earnings by the weighted average shares of common stock outstanding during the reporting period. Diluted EPS is calculated by dividing net earnings by the weighted average shares of common stock and common stock equivalents outstanding during the reporting period.
The dilutive impact of stock-based compensation is calculated using the treasury stock method. The treasury stock method assumes that the Company uses the assumed proceeds from the exercise of awards to repurchase common stock at the average market price during the period. The assumed proceeds under the treasury stock method include the purchase price that the grantee will pay in the future and compensation cost for future service that the Company has not yet recognized.
The following table reconciles the numerators and denominators used to calculate basic and diluted earnings per share of common stock:
Year Ended December 31,
(in millions, except per share amounts)202520242023
Basic earnings per share:   
Net earnings attributable to PHINIA Inc.$130 $79 $102 
Weighted average shares of common stock outstanding39.344.0 46.9 
Basic earnings per share of common stock$3.31 $1.80 $2.17 
Diluted earnings per share:  
Net earnings attributable to PHINIA Inc.$130 $79 $102 
Weighted average shares of common stock outstanding39.344.0 46.9 
Effect of stock-based compensation0.80.8 0.1 
Weighted average shares of common stock outstanding including dilutive shares 40.144.8 47.0 
Diluted earnings per share of common stock$3.24 $1.76 $2.17 

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.