UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 19, 2015

MICROSEMI CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	0-8866	95-2110371
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

One Enterprise, Aliso Viejo, California	92656
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code
(949) 380-6100

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

x Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

INFORMATION TO BE INCLUDED IN THE REPORT

Item 8.01 Other Events.

On October 19, 2015, Microsemi Corporation (“Microsemi”) issued a press release announcing that it has delivered to the board of directors of PMC-Sierra, Inc. (“PMC-Sierra”) a proposal to acquire all of the outstanding shares of PMC-Sierra common stock for a per share consideration of $8.75 in cash and 0.0736 of a share of Microsemi common stock. A copy of the press release, which includes a copy of the letter to the board of directors of PMC-Sierra containing the proposal, is attached hereto as Exhibit 99.1 and incorporated herein by reference. As described in the press release, Microsemi executives will discuss the proposed transaction with analysts and investors on a conference call at 8:30 a.m. ET on October 19, 2015. A copy of the investor presentation related to the conference call is attached hereto as Exhibit 99.2 and incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.	Description
99.1	Press release issued by Microsemi Corporation on October 19, 2015.
99.2	Investor presentation.

Cautionary Note Concerning Forward-Looking Statements

This document contains forward-looking statements based on current expectations or beliefs, as well as a number of assumptions about future events, and these statements are subject to factors and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. The reader is cautioned not to put undue reliance on these forward-looking statements, which are not a guarantee of future performance and are subject to a number of uncertainties and other factors, many of which are outside the control of Microsemi. The forward-looking statements in this document address a variety of subjects including, for example, statements regarding Microsemi’s offer to acquire PMC-Sierra Inc. (“PMC”), its financing and the expected timing of the proposed transaction, the potential benefits of the acquisition (including the potentially accretive and synergistic benefits), Microsemi’s expected future performance (including expected results of operations and financial guidance), and the combined company’s future financial condition, operating results, strategy and plans. Statements including words such as “believes,” “expects,” “anticipates,” “intends,” “estimates,” “plan,” “will,” “may,” “look forward,” “intend,” “guidance,” “future” or similar expressions are forward-looking statements. Potential risks and uncertainties include, but are not limited to, such factors as the ultimate outcome of any possible transaction between Microsemi and PMC, including the possibilities that Microsemi will not pursue a transaction with PMC or that PMC will reject a transaction with Microsemi; if a transaction between Microsemi and PMC were to occur, the ultimate outcome and results of integrating the operations of Microsemi and PMC, the ultimate outcome of Microsemi’s operating strategy applied to PMC and the ultimate ability to realize synergies; the effects of the business combination of Microsemi and PMC, including the combined company’s future financial condition, operating results, strategy and plans; negative or worsening worldwide economic conditions or market instability; downturns in the highly cyclical semiconductor industry; our ability to successfully implement our acquisitions strategy or integrate other acquired companies; uncertainty as to the future profitability of acquired businesses, and delays in the realization of, or the failure to realize, any accretion from acquisition transactions; acquiring, managing and integrating new operations, businesses or assets, and the associated diversion of management attention or other related costs or difficulties; Microsemi's reliance on government contracts for a significant portion of its sales, including impacts of any termination or renegotiation of such contracts, uncertainties of governmental appropriations and national defense policies and priorities and effects of any past or future government shutdowns; risks related to the company's international operations and sales, including political instability, trade restrictions and sanctions, restrictions in the transfer or repatriation of funds, currency fluctuations and availability of transportation services; potential non-realization of expected orders or non-realization of backlog; failure to make sales indicated by the company's book-to-bill ratio; intense competition in the semiconductor industry and resultant downward price pressure; the effect of events such as natural

disasters and related disruptions on our operations; the concentration of the factories that service the semiconductor industry; delays in beginning production, implementing production techniques, resolving problems associated with technical equipment malfunctions, or issues related to government or customer qualification of facilities; our dependence on third parties for key functions; increases in the costs of credit and the availability of credit or additional capital only under more restrictive conditions or not at all; changes to laws or regulations; unanticipated changes in Microsemi's tax obligations, results of tax examinations or exposure to additional income tax liabilities; changes in generally accepted accounting principles; principal, liquidity and counterparty risks related to Microsemi's holdings in securities; inability to develop new technologies and products to satisfy changes in customer demand or the development by the company's competitors of products that decrease the demand for Microsemi's products; unfavorable or declining conditions in end markets; inability of Microsemi's compound semiconductor products to compete successfully with silicon-based products; production delays related to new compound semiconductors; variability of the company's manufacturing yields; potential effects of system outages; inability by Microsemi to fulfill customer demand and resulting loss of customers; variations in customer order preferences; difficulties foreseeing future demand; rises in inventory levels and inventory obsolescence; environmental or other regulatory matters or litigation, or any matters involving contingent liabilities or other claims; the uncertainty of litigation, the costs and expenses of litigation, the potential material adverse effect litigation could have on Microsemi's business and results of operations if an adverse determination in litigation is made, and the time and attention required of management to attend to litigation; difficulties in determining the scope of, and procuring and maintaining, adequate insurance coverage; difficulties and costs of protecting patents and other proprietary rights; the hiring and retention of qualified personnel in a competitive labor market; any circumstances that adversely impact the end markets of acquired businesses; and difficulties in closing or disposing of operations or assets or transferring work, assets or inventory from one plant to another. In addition to these factors and any other factors mentioned elsewhere in this document, the reader should refer as well to the factors, uncertainties or risks identified in Microsemi's most recent Form 10-K and any subsequent Form 10-Q reports filed by Microsemi with the SEC. Additional risk factors may be identified from time to time in Microsemi's future filings. The forward-looking statements included in this document speak only as of the date hereof, and Microsemi does not undertake any obligation to update these forward-looking statements to reflect subsequent events or circumstances.

Additional Information and Where to Find It

This communication does not constitute an offer to buy or solicitation of an offer to sell any securities. This communication relates to a proposal which Microsemi Corporation (“Microsemi”) has made for a business combination transaction with PMC-Sierra Inc. (“PMC”). In furtherance of this proposal and subject to future developments, Microsemi (and, if a negotiated transaction is agreed to, PMC) may file one or more registration statements, prospectuses, proxy statements or other documents with the U.S. Securities and Exchange Commission (“SEC”). This communication is not a substitute for any registration statement, prospectus, proxy statement or other document Microsemi and/or PMC may file with the SEC in connection with the proposed transaction. INVESTORS AND SECURITY HOLDERS OF MICROSEMI AND PMC ARE URGED TO READ THE REGISTRATION STATEMENT, PROSPECTUS, PROXY STATEMENT AND OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE AS THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. Any definitive proxy statement (if and when available) will be mailed to stockholders of PMC. Investors and security holders will be able to obtain free copies of these documents (if and when available) and other documents filed with the SEC by Microsemi through the web site maintained by the SEC at http://www.sec.gov.

Certain Information Regarding Participants

Microsemi and certain of its directors and executive officers may be deemed to be participants in any solicitation with respect to the proposed transaction under the rules of the SEC. Security holders may obtain information regarding the names and interests of Microsemi’s directors and executive officers from Microsemi’s Annual Report on Form 10-K for the year ended September 28, 2014, which was filed with the SEC on November 13, 2014, and Microsemi’s proxy statement for the 2015 Annual Meeting of Shareholders, which was filed with the SEC on December 19, 2014. These documents can be obtained free of charge from the sources indicated above. Additional information regarding the interests of these participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will also be included in any proxy statement and other relevant materials to be filed with the SEC if and when they become available.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MICROSEMI CORPORATION (Registrant)
Date: October 19, 2015	By:	/s/ John W. Hohener
		Name: John W. Hohener Title: Executive Vice President, Chief Financial Officer, Secretary and Treasurer

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press release issued by Microsemi Corporation on October 19, 2015.
99.2	Investor presentation.