11. Earnings Per Share

Basic earnings per share represents net income divided by the weighted-average number of common shares outstanding for the period. Diluted earnings per share represents net income divided by the weighted-average number of common shares outstanding, inclusive of the effect of dilutive securities, such as outstanding SARs and stock units.

The following are the common share amounts used to compute the basic and diluted earnings per share for each period:

There were an aggregate of 1.3 million and 5.3 million of equity grants, consisting of SARs, and stock units that were outstanding during the three months ended March 31, 2018 and 2017, respectively, but were not included in the computation of diluted earnings per share because their effect would be anti-dilutive or the performance condition for the award had not been satisfied.

Since the Company will settle the principal amount of its 2019 Convertible Notes in cash and settle the conversion feature for the amount above the conversion price in common shares, or the conversion spread, the Company uses the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted earnings per share, if applicable. The conversion spread will have a dilutive impact on diluted earnings per share when the average market price of the Company’s common shares for a given period exceeds the initial conversion price of $86.28 per share. For the three months ended March 31, 2018 and 2017, the 2019 Convertible Notes have been excluded from the computation of diluted earnings per share, as the effect would be anti-dilutive since the conversion price of the 2019 Convertible Notes exceeded the average market price of the Company’s common shares for the three months ended March 31, 2018 and 2017. The initial conversion rate and conversion price for the 2019 Convertible Notes are described further in Note 4, Long-Term Debt.

For the 2024 Convertible Notes, the Company has the intent and ability to settle the principal amount in cash and intends to settle the conversion feature for the amount above the conversion price, or the conversion spread, in common shares. The Company uses the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted earnings per share, if applicable. The conversion spread will have a dilutive impact on diluted earnings per share when the average market price of the Company’s common shares for a given period exceeds the initial conversion price of $124.96 per share. For the three months ended March 31, 2018, the 2024 Convertible Notes have been excluded from the computation of diluted earnings per share, as the effect would be anti-dilutive since the conversion price of the 2024 Convertible Notes exceeded the average market price of the Company’s common shares for the three months ended March 31, 2018. The initial conversion rate and conversion price for the 2024 Convertible Notes are described further in Note 4, Long-Term Debt.

The Capped Call Transactions are excluded from the calculation of diluted earnings per share because their impact is always anti-dilutive. Additionally, the Forward Transactions are treated as retired shares for basic and diluted EPS purposes, although they remain legally outstanding. See Note 10, Shareholders’ Deficit, for additional discussion regarding the Capped Call Transactions and Forward Transactions.

See Note 10, Shareholders’ Deficit, for a discussion of how common shares repurchased by the Company’s indirect wholly-owned subsidiary are treated under U.S. GAAP.