Exhibit 99.1

PLEXUS CORP.

NON-GAAP SUUPLEMENTAL INFORMATION

(in thousands, except per share data)

(unaudited)

ROIC Calculation

	Nine Months Ended				Six Months Ended				Nine Months Ended
	June 29, 2013				March 30, 2013				June 30, 2012
Operating income	$	69,856			$	44,672			$	76,810
	/		3		/		2		/		3
	23,285				22,336				25,603
	x		4		x		4		x		4
Annualized operating income	93,140				89,344				102,413
Tax rate	x		8	%	x		8	%	x		9	%
Tax impact			7,451				7,148				9,217
Operating income (tax effected)	$	85,689			$	82,196			$	93,196
Average invested capital	$	647,971			$	645,402			$	623,320
ROIC	13.2			%	12.7			%	15.0			%

	June 29, 2013			March 30, 2013			December 29, 2012			September 29, 2012
Equity	$	679,539		$	669,047		$	664,515		$	649,022
Plus:
Debt—current	2,984			2,893			10,310			10,211
Debt—non-current	258,758			258,789			259,516			260,211
Less:
Cash and cash equivalents	(285,604		)	(276,507		)	(274,183		)	(297,619		)
	$	655,677		$	654,222		$	660,158		$	621,825

Fiscal 2013 third quarter average invested capital (June 29, 2013, March 30, 2013, December 29, 2012 and September 29, 2012) was $647,971.

Fiscal 2013 second quarter average invested capital (March 30, 2013, December 29, 2012 and September 29, 2012) was $645,402.

	June 30, 2012			March 31, 2012			December 31, 2011			October 1, 2011
Equity	$	638,573		$	615,296		$	581,811		$	558,882
Plus:
Debt—current	13,838			17,518			17,446			17,350
Debt—non-current	260,843			261,542			265,941			270,292
Less:
Cash and cash equivalents	(277,909		)	(257,754		)	(248,284		)	(242,107		)
	$	635,345		$	636,602		$	616,914		$	604,417

Fiscal 2012 third quarter average invested capital (June 30, 2012, March 31, 2012, December 31, 2011 and October 1, 2011) was $623,320.