Earnings Per Share

3 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]

Earnings Per Share

Earnings Per Share

Basic earnings per share (“EPS”) is computed by dividing net income attributable to Amkor common shareholders 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. Unvested share-based compensation awards that contain nonforfeitable rights to dividends or dividend equivalents are considered participating securities and are included in the computation of EPS pursuant to the two-class method. We grant restricted shares which entitle recipients to voting and nonforfeitable dividend rights from the date of grant. As a result, we have applied the two-class method to determine EPS.

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,
	2012			2011
	(In thousands, except per share data)
Net income attributable to Amkor	$	11,774		$	25,103
Income allocated to participating securities	(38		)	(116		)
Net income available to Amkor common stockholders	11,736			24,987
Adjustment for dilutive securities on net income:
Net income allocated to participating securities in basic calculation	38			116
Interest on 6.0% convertible notes due 2014, net of tax	4,026			4,026
Net income attributable to Amkor — diluted	$	15,800		$	29,129
Weighted average shares outstanding — basic	167,866			194,067
Effect of dilutive securities:
Stock options	164			417
Unvested restricted shares	—			443
6.0% convertible notes due 2014	82,658			82,658
Weighted average shares outstanding — diluted	250,688			277,585
Net income attributable to Amkor per common share:
Basic	$	0.07		$	0.13
Diluted	0.06			0.10

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,
	2012	2011
	(In thousands)
Stock options and restricted share awards	4,408	5,531
2.5% convertible notes due 2011	—	2,918
6.25% convertible notes due 2013	—	2,819
Total potentially dilutive shares	4,408	11,268