| EARNINGS PER SHARE The computation of basic and diluted earnings per common share was as follows (in millions, except per share data): | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | | | 2025 | | 2024 | | 2025 | | 2024 | | Amounts attributable to Quest Diagnostics’ common stockholders: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Net income attributable to Quest Diagnostics | $ | 282 | | | $ | 229 | | | $ | 502 | | | $ | 423 | | | Less: Earnings allocated to participating securities | 1 | | | 1 | | | 2 | | | 2 | | Earnings available to Quest Diagnostics’ common stockholders – basic and diluted | $ | 281 | | | $ | 228 | | | $ | 500 | | | $ | 421 | | | | | | | | | | | Weighted average common shares outstanding – basic | 112 | | | 111 | | | 112 | | | 111 | | | Effect of dilutive securities: | | | | | | | | | Stock options and performance share units | 1 | | | 1 | | | 1 | | | 1 | | | Weighted average common shares outstanding – diluted | 113 | | | 112 | | | 113 | | | 112 | | | | | | | | | | | Earnings per share attributable to Quest Diagnostics’ common stockholders: | | | | | | | | | Basic | $ | 2.51 | | | $ | 2.05 | | | $ | 4.48 | | | $ | 3.79 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Diluted | $ | 2.47 | | | $ | 2.03 | | | $ | 4.41 | | | $ | 3.75 | | | | | | | | | | | | | | | | | |
The following securities were not included in the calculation of diluted earnings per share due to their antidilutive effect: | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended June 30, | | Six Months Ended June 30, | | 2025 | | 2024 | | 2025 | | 2024 | | Stock options and performance share units | — | | | 1 | | | — | | | 1 | |
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