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 30, 2012				March 31, 2012				July 2, 2011
Operating income	$	76,810			$	49,530			$	79,144
	÷		3		÷		2		÷		3
	25,603				24,765				26,381
	x		4		x		4		x		4
Annualized operating income	102,413				99,060				105,524
Tax rate	9			%	10			%	3			%
Tax impact	-		9,217		-		9,906		-		3,166
Operating income (tax effected)	$	93,196			$	89,154			$	102,358
Average invested capital	$	623,320			$	619,311			$	633,408
ROIC	15.0			%	14.4			%	16.2			%

	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, October 1, 2011) was $623,320

Fiscal 2012 second quarter average invested capital (March 31, 2012, December 31, 2011, October 1, 2011) was $619,311

	July 2, 2011			April 2, 2011			January 1, 2011			October 2, 2010
Equity	$	572,657		$	630,403		$	680,474		$	651,855
Plus:
Debt—current	17,191			17,119			17,052			17,409
Debt—non-current	274,677			103,961			108,220			112,466
Less:
Cash and cash equivalents	(208,729		)	(123,381		)	(149,498		)	(188,244		)
	$	655,796		$	628,102		$	656,248		$	593,486

Fiscal 2011 third quarter average invested capital (July 2, 2011, April 2, 2011, January 1, 2011, October 2, 2010) was $633,408