Microsemi (MSCC) 8-K/A Financial Statements and Exhibits

Exhibit 99.4

MICROSEMI CORPORATION

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

As previously disclosed, Microsemi Corporation (“Microsemi”), through its indirect wholly-owned subsidiary 0916753 B.C. ULC (“Purchaser”), completed its acquisition of Zarlink Semiconductor Inc. (“Zarlink”) pursuant to the previously announced Support Agreement dated September 21, 2011 by and among Microsemi, Purchaser and Zarlink. Following the expiration of the previously announced offers for all of the issued and outstanding common shares (“Zarlink Shares”) and 6% unsecured, subordinated convertible debentures maturing September 30, 2012 (“Zarlink Debentures” and together with the Zarlink Shares, the “Zarlink Securities”) of Zarlink, Purchaser acquired all remaining Zarlink Shares and Zarlink Debentures through compulsory acquisitions under, respectively, the Canada Business Corporations Act and the trust indenture governing the Zarlink Debentures.

The unaudited pro forma condensed combined balance sheet combines Microsemi’s July 3, 2011 consolidated balance sheet with Zarlink’s June 24, 2011 unaudited consolidated balance sheet. The unaudited pro forma condensed combined balance sheet gives pro forma effect as if the Zarlink acquisition had been completed on July 3, 2011.

The unaudited pro forma condensed combined income statements combine Microsemi’s consolidated income statement, adjusted for the pro forma impact of our acquisitions of Asic Advantage, Inc. (“Asic”), AML Communications, Inc. (“AML”), Actel Corporation (“Actel”), White Electronic Designs Corporation (“White Electronic”), VT Silicon and Arxan Defense Systems, Inc. (“ADS”), for a) the twelve months ended October 3, 2010 with Zarlink’s unaudited consolidated statement of income for the twelve months ended September 24, 2011 and b) the nine-months ended July 3, 2011 with Zarlink’s unaudited consolidated statement of income for the nine-months ended June 24, 2011. The acquisitions of Asic, AML, Actel, White Electronic, VT Silicon and ADS occurred on July 5, 2011, May 27, 2011, November 2, 2010, April 30, 2010, September 10, 2010 and September 14, 2010, respectively. The unaudited pro forma condensed income statement gives pro forma effect as if all acquisitions had been completed on September 28, 2009.

The pro forma information presented is for illustrative purposes only and is not necessarily indicative of the financial position or results of operations that would have been realized if the acquisitions had been completed on the dates indicated, nor is it indicative of future operating results or financial position. The pro forma adjustments are based upon currently available information and certain assumptions that Microsemi believes are reasonable under the circumstances.

A final determination of fair values relating to the Zarlink acquisition may differ materially from preliminary estimates and will include management’s final valuation of the fair value of assets acquired and liabilities assumed. This final valuation will be based on the actual net tangible and intangible assets of Zarlink that existed as of the date of the completion of the Zarlink acquisition. The final valuation may materially change the allocation of the purchase price, which could materially affect the fair values assigned to the assets and liabilities and could result in a material change to the unaudited pro forma condensed combined financial statements.

These unaudited pro forma condensed combined financial statements should be read in conjunction with the historical consolidated financial statements and related notes contained in the annual, quarterly and other reports filed by Microsemi, Zarlink, AML, Actel and White Electronic with the Securities and Exchange Commission.

MICROSEMI CORPORATION

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

AS OF July 3, 2011

(in thousands)

	Historical Microsemi		Historical Zarlink			Pro Forma Adjustments					Pro Forma Combined
ASSETS
Current assets:
Cash and cash equivalents	$	246,246	$	130,744		$	(624,835	)	(1	)	$	200,831
							448,676		(2	)
Accounts receivable		98,066		22,002			—					120,068
Inventories		145,352		24,842			7,647		(3	)		177,841
Deferred income taxes		14,984		1,313			—					16,297
Other current assets		31,082		1,528			—					32,610
Total current assets		535,730		180,429			(168,512	)				547,647
Property and equipment, net		89,899		7,828			—					97,727
Goodwill		543,286		—			295,615		(4	)		838,901
Other intangible assets, net		290,160		32,814			178,786		(5	)		501,760
Deferred income tax assets		—		36,812			—					36,812
Other assets		25,946		7,659			—					33,605
TOTAL ASSETS	$	1,485,021	$	265,542		$	305,889				$	2,056,452
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	40,063	$	14,255		$	—				$	54,318
Accrued liabilities		81,390		19,683			—					101,073
Current maturities of long-term liabilities		4,220		—			4,760		(6	)		8,980
Total current liabilities		125,673		33,938			4,760					164,371
Credit facility and long-term debt		368,452		71,950			473,048		(6	)		841,500
							(71,950	)	(7	)
Deferred income taxes		116,021		—			84,640		(8	)		200,661
Other long-term liabilities		33,656		4,177			—					37,833
Redeemable preferred shares		—		12,372			(12,372	)	(7	)		—
Stockholders’ equity:
Common stock		17,335		725,618			(725,618	)	(9	)		17,335
Capital in excess of par value of common stock		604,638		45,664			(45,664	)	(9	)		604,638
Retained earnings (deficit)		218,075		(594,983	)		594,983		(9	)		188,943
							(28,199	)	(6	)
							(933	)	(6	)
Accumulated other comprehensive income (loss)		1,171		(33,194	)		33,194		(9	)		1,171
Total stockholders’ equity		841,219		143,105			(172,237	)				812,087
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$	1,485,021	$	265,542		$	305,889				$	2,056,452

The total estimated consideration as shown in the table below is preliminarily allocated to Zarlink’s tangible and intangible assets and liabilities based on their estimated fair values as of the date of the completion of the transaction. The preliminary estimated consideration is allocated as follows (in thousands):

Calculation of consideration:
Cash consideration for Zarlink Securities(1)	$	624,835
Preliminary allocation of consideration:
Book value of Zarlink’s net assets		143,105
Adjustments to historical net book value:
Inventories (3)		7,647
Other intangible assets, net (5)		178,786
Long-term debt and redeemable preferred shares (7)		84,322
Deferred tax liability (8)		(84,640	)
Adjustment to goodwill (4)	$	295,615

(1) Amount represents the cash consideration for all of the Zarlink Securities acquired pursuant to the previously announced Support Agreement dated September 21, 2011 by and among Microsemi, Purchaser and Zarlink.

(2) Amount represents the net proceeds from incremental borrowings under Amendment No. 2 to Microsemi’s existing Credit Agreement dated as of November 2, 2010, as amended by Amendment No. 1 to the Credit Agreement, dated as of March 2, 2011, with Morgan Stanley Senior Funding, Inc., Morgan Stanley & Co. LLC and the lenders referred to therein (as amended, the “Amended and Restated Credit Agreement”).

(3) Amount represents the adjustment to mark up inventories acquired from Zarlink to their estimated fair value less cost to sell.

(4) The preliminary allocation of purchase price resulted in the allocation of an incremental $295.6 million to goodwill. The factors that contributed to a purchase price resulting in the recognition of goodwill include:

• The premium paid over the market capitalization of Zarlink immediately prior to the merger announcement.

• Our belief that the merger will create a more diverse semiconductor company with expansive offerings which will enable us to expand our product offerings.

• Our belief that both companies are each committed to improving cost structures and that our combined efforts after the merger should result in a realization of cost savings and an improvement of overall efficiencies.

(5) Of the total estimated consideration, we allocated an incremental $178.8 million to other intangible assets, net. The preliminary allocation of identifiable intangible assets and their estimated useful lives are as follows (in thousands):

Preliminary allocation of identifiable intangible assets:	Asset Amount			Weighted Average Useful Life (Years)
Complete technology	$	47,800		6
Backlog		17,100		1
Customer relationships		145,000		6
Trade name		1,700		2
		211,600
Amount reported on historical Zarlink balance sheet		(32,814	)
Adjustment to other identifiable intangible assets, net (5)	$	178,786

(6) Amounts represent additional borrowings on the Amended and Restated Credit Agreement such that the total amount outstanding is $850.0 million, a charge of $28.2 million related to fees and costs for the Amended and Restated Credit Agreement and a reversal of fair value adjustments of $0.9 million related to pre-amendment amounts outstanding on the credit agreement.

(7) Amounts represent the elimination of balances related to the Zarlink Securities.

(8) Amount represents the deferred tax liability related to the preliminary allocation of identifiable intangible assets.

(9) Amounts represent the elimination of Zarlink’s historical equity accounts.

MICROSEMI CORPORATION

UNAUDITED PRO FORMA CONDENSED COMBINED INCOME STATEMENT

FOR THE TWELVE MONTHS ENDED OCTOBER 3, 2010

(In thousands, except per share amounts)

	Pro Forma Microsemi (6)			Historical Zarlink			Pro Forma Adjustments					Pro Forma Combined
Net sales	$	806,331		$	223,751		$	—				$	1,030,082
Cost of sales		398,240			108,063			7,647		(1	)		513,950
Gross profit		408,091			115,688			(7,647	)				516,132
Operating expenses:
Selling and general and administrative		212,858			43,581			—					256,439
Amortization of intangible assets		78,985			6,943			43,141		(2	)		129,069
Research and development costs		124,550			41,445			—					165,995
Restructuring and severance charges		14,200			—			—					14,200
Total operating expenses		430,593			91,969			43,141					565,703
Operating income (loss)		(22,502	)		23,719			(50,788	)				(49,571	)
Interest and other income (expense), net		(30,783	)		(8,030	)		(31,226	)	(3	)		(65,362	)
								4,677		(4	)
Income (loss) before income taxes		(53,285	)		15,689			(77,337	)				(114,933	)
Provision (benefit) for income taxes		36,583			(3,358	)		(30,935	)	(5	)		2,290
Net income (loss)	$	(89,868	)	$	19,047		$	(46,402	)			$	(117,223	)
Net income per share:
Basic	$	(1.11	)									$	(1.45	)
Diluted	$	(1.11	)									$	(1.45	)
Weighted-average common shares outstanding:
Basic		80,797											80,797
Diluted		80,797											80,797

(1) Amount reflects the impact in cost of goods sold from the estimated manufacturing profit in acquired inventory.

(2) Amount reflects amortization of intangibles related to the preliminary estimate of fair value of intangible assets acquired. We expect to utilize the straight line method of amortization for completed technology, customer relationships and trade name and the estimated fulfillment period for backlog. Calculation of pro forma amortization expense for the 12-month pro forma period is as follows (in thousands):

Preliminary allocation of identifiable intangible assets:	Amortization Expense
Complete technology	$	7,967
Backlog		17,100
Customer relationships		24,167
Trade name		850
		50,084
Amount reported on historical Zarlink statements		(6,943	)
Adjustment to other identifiable intangible assets, net	$	43,141

(3) Amount represents the interest expense from borrowings incurred to fund the Zarlink acquisition. The pro forma weighted average term loan balance used was $796.5 million, representing the minimum allowable amortization of principal during the pro forma period. The pro forma revolver balance used was $50.0 million, outstanding for three months. The weighted average interest rate used was 5.75%, reflecting LIBOR during the pro forma period below the 1.25% LIBOR floor and a 4.5% LIBOR spread in accordance with the terms of Microsemi’s Amended and Restated Credit Facility. These assumptions resulted in interest expense of $46.5 million compared to $15.3 million of interest expense related to the credit facility in the “Pro Forma Microsemi” column or a difference of $31.2 million.

(4) Amount represents interest expense and amortization of debt issuance costs reported in the “Historical Zarlink” column as Zarlink Debentures were assumed to be redeemed at the beginning of the pro forma period.

(5) Amount reflects the estimated pro forma tax effect of the above adjustments.

(6) The following supplemental pro forma data summarizes the results of operations for the year ended October 3, 2010, as if the acquisitions of Asic, AML, Actel, White Electronic, VT Silicon and ADS had occurred on September 27, 2009. The pro forma adjustments are based upon currently available information and certain assumptions that we believe are reasonable under the circumstances. The supplemental pro forma data reports actual operating results, adjusted to include the pro forma effect of, among others, the impact in cost of goods sold from manufacturing profit in acquired inventory, amortization expense of identified intangible assets, timing of the impact of restructuring expenses, timing of credit facility issuance costs, incremental interest expense and the related tax effect of these items. Supplemental pro forma earnings were adjusted to include $5.9 million in cost of goods sold from manufacturing profit in acquired inventory, $8.6 million in acquisition costs, $14.2 million in credit facility issuance costs, and $5.0 million in non-cash benefits of valuation allowance releases that were incurred in the year ended October 2, 2011 but would have been incurred in the pro forma period had the acquisitions occurred on September 27, 2009. The pro forma data is as follows (in thousands):

	Historical Microsemi			Pro Forma Adjustments			Pro Forma Microsemi
Net sales	$	518,268		$	288,063		$	806,331
Cost of sales		270,057			128,183			398,240
Gross profit		248,211			159,880			408,091
Operating expenses:
Selling and general and administrative		114,663			98,195			212,858
Amortization of intangible assets		20,165			58,820			78,985
Research and development costs		55,395			69,155			124,550
Restructuring and severance charges		2,107			12,093			14,200
Total operating expenses		192,330			238,263			430,593
Operating income (loss)		55,881			(78,383	)		(22,502	)
Interest and other income (expense), net		(850	)		(29,933	)		(30,783	)
Income (loss) before income taxes		55,031			(108,316	)		(53,285	)
Provision (benefit) for income taxes		(4,007	)		40,590			36,583
Net income (loss)	$	59,038		$	(148,906	)	$	(89,868	)

MICROSEMI CORPORATION

UNAUDITED PRO FORMA CONDENSED COMBINED INCOME STATEMENT

FOR THE NINE MONTHS ENDED JULY 3, 2011

(In thousands, except per share amounts)

	Pro Forma Microsemi (5)			Historical Zarlink			Pro Forma Adjustments					Pro Forma Combined
Net sales	$	636,370		$	167,095		$	—				$	803,465
Cost of sales		304,347			79,706			—					384,053
Gross profit		332,023			87,389			—					419,412
Operating expenses:
Selling and general and administrative		137,355			21,213			—					158,568
Amortization of intangible assets		57,239			5,208			19,530		(1	)		81,977
Research and development costs		86,901			32,396			—					119,297
Restructuring and severance charges		14,766			—			—					14,766
Total operating expenses		296,261			58,817			19,530					374,608
Operating income (loss)		35,762			28,572			(19,530	)				44,804
Interest and other income (expense), net		(14,419	)		(4,898	)		(23,675	)	(2	)		(39,315	)
								3,677		(3	)
Income (loss) before income taxes		21,343			23,674			(39,528	)				5,489
Benefit for income taxes		(5,609	)		(30,343	)		(15,811	)	(4	)		(51,763	)
Net income (loss)	$	26,952		$	54,017		$	(23,717	)			$	57,252
Net income per share:
Basic	$	0.33										$	0.70
Diluted	$	0.32										$	0.68
Weighted-average common shares outstanding:
Basic		82,317											82,317
Diluted		84,297											84,297

(1) Amount reflects amortization of intangibles related to the preliminary estimate of fair value of intangible assets acquired. We expect to utilize the straight line method of amortization for completed technology, customer relationships and trade name. Amortization of backlog would have been completed in the 12-month pro forma period ended October 3, 2010. Calculation of pro forma amortization expense for the 9-month pro forma period is as follows (in thousands):

Preliminary allocation of identifiable intangible assets:	Amortization Expense
Complete technology	$	5,975
Customer relationships		18,125
Trade name		638
		24,738
Amount reported on historical Zarlink statements	$	(5,208	)
Adjustment to other identifiable intangible assets, net	$	19,530

(2) Amount represents the interest expense from borrowings incurred to fund the Zarlink acquisition. The pro forma weighted average term loan balance used was $798.0 million, representing the minimum allowable amortization of principal during the pro forma period. The pro forma revolver balance used was $50.0 million, outstanding for three months. The weighted average interest rate used was 5.75%, reflecting LIBOR during the pro forma period below the 1.25% LIBOR floor and a 4.5% LIBOR spread in accordance with the terms of Microsemi’s Amended and Restated Credit Facility. These assumptions resulted in interest expense of $35.2 million compared to $11.5 million of interest expense related to the credit facility in the “Pro Forma Microsemi” column or a difference of $23.7 million.

(3) Amount represents interest expense and amortization of debt issuance costs reported in the “Historical Zarlink” column as Zarlink Debentures were assumed to be redeemed at the beginning of the pro forma period.

(4) Amount reflects the estimated pro forma tax effect of the above adjustments.

(5) The following supplemental pro forma data summarizes the results of operations for the year ended October 3, 2010, as if the acquisitions of Asic, AML, Actel, White Electronic, VT Silicon and ADS had occurred on September 27, 2009. The pro forma adjustments are based upon currently available information and certain assumptions that we believe are reasonable under the circumstances. The supplemental pro forma data reports actual operating results, adjusted to include the pro forma effect of, among others, the impact in cost of goods sold from manufacturing profit in acquired inventory, amortization expense of identified intangible assets, timing of the impact of restructuring expenses, timing of credit facility issuance costs, incremental interest expense and the related tax effect of these items. Supplemental pro forma earnings were adjusted to exclude $5.5 million in cost of goods sold from manufacturing profit in acquired inventory, $8.6 million in acquisition costs, $14.2 million in credit facility issuance costs, and $12.1 million in non-cash benefits of valuation allowance releases that were incurred during the period but would have been incurred in a prior period had the acquisitions occurred on September 27, 2009. The pro forma data is as follows (in thousands):

	Historical Microsemi			Pro Forma Adjustments			Pro Forma Microsemi
Net sales	$	608,563		$	27,807		$	636,370
Cost of sales		297,267			7,080			304,347
Gross profit		311,296			20,727			332,023
Operating expenses:
Selling and general and administrative		138,302			(947	)		137,355
Amortization of intangible assets		44,783			12,456			57,239
Research and development costs		81,712			5,189			86,901
Restructuring and severance charges		20,271			(5,505	)		14,766
Total operating expenses		285,068			11,193			296,261
Operating income (loss)		26,228			9,534			35,762
Interest and other income (expense), net		(26,315	)		11,896			(14,419	)
Income (loss) before income taxes		(87	)		21,430			21,343
Provision (benefit) for income taxes		(12,449	)		6,840			(5,609	)
Net income (loss)	$	12,362		$	14,590		$	26,952