8. Earnings Per Share

9 Months Ended

Sep. 30, 2019

. EARNINGS (LOSS) PER SHARE

Basic earnings (loss) per share is computed by dividing net income attributable to Bio-Rad by the weighted average number of common shares outstanding for that period. Diluted earnings (loss) per share takes into account the effect of dilutive instruments, such as stock options and restricted stock, and uses the average share price for the period in determining the number of potential common shares that are to be added to the weighted average number of shares outstanding. Potential common shares are excluded from the diluted earnings (loss) per share calculation if the effect of including such securities would be anti-dilutive. For the three months ended September 30, 2019, net loss per basic share was the same as net loss per diluted share because all potentially dilutive shares were anti-dilutive due to the net loss for the period.

The weighted average number of common shares outstanding used to calculate basic and diluted earnings per share, and the anti-dilutive shares that are excluded from the diluted earnings per share calculation are as follows (in thousands):



	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2019	2018	2019	2018
Basic weighted average shares outstanding	29,831	29,863	29,815	29,822
Effect of potentially dilutive stock options and restricted stock awards	—	429	334	412
Diluted weighted average common shares	29,831	30,292	30,149	30,234
Anti-dilutive shares	95	64	56	35