Earnings Per Share

3 Months Ended

Mar. 31, 2014

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,
	2014			2013
	(In thousands, except per share data)
Net income attributable to Amkor	$	20,633		$	13,382
Income allocated to participating securities	(105		)	(66		)
Net income available to Amkor common stockholders — basic	20,528			13,316
Adjustment for dilutive securities on net income:
Net income reallocated to participating securities	3			66
Interest on 6.0% convertible notes due 2014, net of tax	907			4,026
Net income attributable to Amkor — diluted	$	21,438		$	17,408
Weighted average shares outstanding — basic	216,757			152,411
Effect of dilutive securities:
Stock options	109			18
6.0% convertible notes due 2014	18,631			82,658
Weighted average shares outstanding — diluted	235,497			235,087
Net income attributable to Amkor per common share:
Basic	$	0.09		$	0.09
Diluted	0.09			0.07

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,
	2014	2013
	(In thousands)
Stock options and restricted share awards	4,265	4,236