Earnings per Share

The Company computes basic earnings per share by dividing income available to common shareholders by the weighted average number of common shares outstanding. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the Company adjusts the weighted average number of shares outstanding to include estimates of additional shares that would be issued if potentially dilutive common shares had been issued. In addition, the Company adjusts income available to common shareholders to include any changes in income or loss that would result from the assumed issuance of the dilutive common shares.

Earnings per share of common stock outstanding were computed as follows:



	Year Ended December 31
	2018		2017		2016
	(Millions Except Share and Per Share Amounts)
Net income attributable to Tenneco Inc.	$	55	$	198	$	347
Basic earnings per share —
Average shares of common stock outstanding	58,625,087		52,796,184		55,939,135
Earnings per average share of common stock	$	0.93	$	3.75	$	6.20
Diluted earnings per share —
Average shares of common stock outstanding	58,625,087		52,796,184		55,939,135
Effect of dilutive securities:
Restricted stock and RSUs	93,546		111,062		175,513
Stock options	40,099		119,665		292,788
Average shares of common stock outstanding including dilutive securities	58,758,732		53,026,911		56,407,436
Earnings per average share of common stock	$	0.93	$	3.73	$	6.15

For the years ended December 31, 2018, 2017 and 2016, the weighted average number of anti-dilutive potential common shares excluded from the calculation above totaled 257,567 shares, 834 shares and 134,361 shares, respectively.