Earnings Per Share

3 Months Ended

Mar. 31, 2015

Earnings Per Share [Abstract]

Earnings Per Share

7.    Earnings Per Share

Basic earnings per share (“EPS”) is computed by dividing net income attributable to Amkor common stockholders by the weighted average number of common shares outstanding during the period. The weighted average number of common shares outstanding includes restricted shares held by retirement eligible recipients and is reduced for treasury stock. We grant restricted shares which entitle recipients to voting and nonforfeitable dividend rights from the date of grant therefore our unvested share-based compensation awards are considered participating securities and are included in the computation of EPS pursuant to the two-class method.

Diluted EPS is computed on the basis of the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period. Dilutive potential common shares include outstanding stock options, unvested restricted shares and convertible debt. The following table summarizes the computation of basic and diluted EPS:

	For the Three Months Ended March 31,
	2015			2014
	(In thousands, except per share data)
Net income attributable to Amkor	$	28,781		$	20,633
Income allocated to participating securities	(68		)	(105		)
Net income available to Amkor common stockholders — basic	28,713			20,528
Adjustment for dilutive securities on net income:
Net income reallocated to participating securities	—			3
Interest on 6.0% convertible notes due 2014, net of tax	—			907
Net income attributable to Amkor — diluted	$	28,713		$	21,438
Weighted average shares outstanding — basic	236,708			216,757
Effect of dilutive securities:
Stock options	716			109
6.0% convertible notes due 2014	—			18,631
Weighted average shares outstanding — diluted	237,424			235,497
Net income attributable to Amkor per common share:
Basic	$	0.12		$	0.09
Diluted	0.12			0.09

The following table summarizes the potential shares of common stock that were excluded from diluted EPS, because the effect of including these potential shares was antidilutive:

	For the Three Months Ended March 31,
	2015	2014
	(In thousands)
Stock options and restricted share awards	1,400	4,265