Exhibit 99.1

PLEXUS CORP.

NON-GAAP SUUPLEMENTAL INFORMATION

(in thousands, except per share data)

(unaudited)

Return on Invested Capital ("ROIC") and Economic Return Calculations

	Three Months Ended					Twelve Months Ended					Three Months Ended
	January 3, 2015					September 27, 2014					December 28, 2013
Operating income	$	28,783				$	100,607				$	21,761
Restructuring charges	1,691					11,280					3,605
Adjusted operating income	$	30,474				$	111,887				$	25,366
	x		4			x		1			x		4
Annualized operating income	121,896					111,887					101,464
Tax rate	x		10	%		x		9	%		x		9	%
Tax impact	12,190							10,070					9,132
Operating income (tax effected)	$	109,706				$	101,817				$	92,332
Average invested capital	$	759,676				$	669,659				$	638,697
ROIC	14.4			%		15.2			%		14.5			%
Weighted average cost of capital ("WACC")	11.0			%		11.0			%		11.0			%
Economic return	3.4			%		4.2			%		3.5			%

										January 3,				September 27,
										2015				2014
Equity										$	792,298			$	781,133
Plus:
Debt—current										4,793				4,368
Debt—non-current										260,990				262,046
Less:
Cash and cash equivalents										(239,685		)		(346,591		)
										$	818,396			$	700,956

First quarter fiscal 2015 average invested capital (January 3, 2015 and September 27, 2014) was $759,676.

		September 27,				June 28,				March 29,				December 28,				September 28,
		2014				2014				2014				2013				2013
Equity		$	781,133			$	760,184			$	736,493			$	722,021			$	699,301
Plus:
Debt—current		4,368				4,232				3,901				3,796				3,574
Debt—non-current		262,046				263,056				256,090				256,949				257,773
Less:
Cash and cash equivalents		(346,591		)		(330,314		)		(323,695		)		(324,156		)		(341,865		)
		$	700,956			$	697,158			$	672,789			$	658,610			$	618,783

Fiscal 2014 average invested capital (September 27, 2014, June 28, 2014, March 29, 2014, December 28, 2013 and September 28, 2013) was $669,659. First quarter fiscal 2013 average invested capital (December 28, 2013 and September 28, 2013) was $638,697.