Net Income Per Common Share

9 Months Ended

Sep. 30, 2016



(Thousands of dollars except per share data)	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Basic
Average common shares outstanding	91,992,854		92,196,458		91,752,482		92,398,962
Net income	$	386,733	$	374,491	$	929,673	$	855,832
Basic net income per common share	$	4.20	$	4.06	$	10.13	$	9.26

Diluted
Average common shares outstanding	91,992,854		92,196,458		91,752,482		92,398,962
Stock options and other contingently issuable shares ⁽¹⁾	2,218,617		1,698,414		2,109,359		1,864,371
Non-vested restricted stock grants	560,336		538,203		559,349		513,054
Average common shares outstanding assuming dilution	94,771,807		94,433,075		94,421,190		94,776,387

Net income	$	386,733	$	374,491	$	929,673	$	855,832
Diluted net income per common share	$	4.08	$	3.97	$	9.85	$	9.03


⁽¹⁾	Stock options and other contingently issuable shares for the three and nine months ended September 30, 2016 excluded 32,633 and 63,310 shares, respectively, due to their anti-dilutive effect. Stock options and other contingently issuable shares for the three and nine months ended September 30, 2015 excluded 34,473 and 31,615 shares, respectively, due to their anti-dilutive effect .

Prior to 2016, the Company used the two-class method of calculating basic and diluted earnings per share as time-based restricted shares were considered a separate class of participating securities since they received non-forfeitable dividends. The time-based restricted shares represented less than 1% of outstanding shares, and therefore the difference between basic and diluted earnings per share under the two-class method and treasury stock method was not significant. Starting in 2016, there will be no additional grants of time-based restricted shares. Accordingly, 2016 basic and diluted earnings per share are calculated using the treasury stock method, and the 2015 calculations are presented under the treasury stock method for comparability.

See Note 11 for the impact of the adoption of ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting" on basic and diluted net income per common share.