SC TO-T/A

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE TO-T/A

Tender Offer Statement Under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

(Amendment No. 9)

Arch Chemicals, Inc.

(Name of Subject Company (Issuer))

LG Acquisition Corp.

an indirect wholly owned subsidiary of

Lonza Group Ltd.

(Name of Filing Persons (Offerors))

Common stock, par value $1.00 per share

(Title of Class of Securities)

03937R102

(CUSIP Number of Class of Securities)

Marc Funk, Esq.

Group General Counsel, Senior Vice President

Lonza Group Ltd.

Münchensteinerstrasse 38

CH-4002 Basel, Switzerland

+41 61 316 81 11

(Name, address and telephone number of person authorized to receive notices and communications on
behalf of filing persons)

Copies of all communications, including communications sent to agent for service, should be sent to:

Scott Waldman, Esq.	Kevin T. Collins, Esq.
Vice President and Secretary	Tobias L. Knapp, Esq.
LG Acquisition Corp.	Jenner & Block LLP
90 Boroline Road	919 Third Avenue
Allendale, New Jersey 07401	New York, New York 10022
(201) 316-9200	(212) 891-1600

CALCULATION OF FILING FEE

Transaction Valuation (1)	Amount of Filing Fee (2)
$1,244,271,815.20	$144,460

(1)	Estimated for purposes of calculating the amount of the filing fee only, in accordance with Rule 0−11(d) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Calculated by multiplying $47.20, the per share tender offer price, by 26,361,691 shares of common stock of Arch Chemicals, Inc., which includes (a) 25,431,974 shares of common stock issued and outstanding; (b) 39,547 shares of common stock subject to outstanding options; (c) 323,778 shares of common stock subject to or deemed subject to outstanding performance unit awards; (d) 289,735 shares of common stock subject to or deemed subject to outstanding restricted stock unit awards; and (e) 276,657 shares of common stock subject to or deemed subject to outstanding phantom share awards.
(2)	The filing fee was calculated in accordance with Rule 0−11 of the Exchange Act and Fee Rate Advisory #5 for fiscal year 2011, issued December 22, 2010. Such fee equals 0.0001161 of the transaction value.
x	Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

Amount Previously Paid: $144,460	Filing Party: LG Acquisition Corp. and Lonza Group Ltd.
Form or Registration No.: Schedule TO-T	Date Filed: July 15, 2011

o	Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.
Check the appropriate boxes below to designate any transactions to which the statement relates:
x	third party tender offer subject to Rule 14d-1.
o	issuer tender offer subject to Rule 13e-4.
o	going-private transaction subject to Rule 13e-3.
o	amendment to Schedule 13D under Rule 13d-2.
Check the following box if the filing is a final amendment reporting the results of the tender offer: o

          This Amendment No. 9 (this “Amendment No. 9”) amends and supplements the Tender Offer Statement on Schedule TO initially filed on July 15, 2011, as previously amended, by (i) LG Acquisition Corp., a Virginia corporation (“Purchaser”) and an indirect wholly owned subsidiary of Lonza Group Ltd., a company organized under the laws of Switzerland (“Parent”), and (ii) Parent (the “Initial Schedule TO” and which, together with this Amendment No. 9 and any previous or additional amendments and supplements thereto, collectively constitute the “Schedule TO”). This Schedule TO relates to the offer by Purchaser to purchase all of the outstanding shares of common stock, par value $1.00 per share (the “Shares”), of Arch Chemicals, Inc., a Virginia corporation (the “Company”), at a price of $47.20 per Share, net to the holder thereof in cash, without interest thereon and less any required withholding of taxes, upon the terms and subject to the conditions set forth in the offer to purchase, dated July 15, 2011 (which, together with any amendments and supplements thereto, collectively constitute the “Offer to Purchase”), and in the related form of letter of transmittal (as it may be amended or supplemented, the “Letter of Transmittal”). Copies of the Offer to Purchase and the Letter of Transmittal are attached to the Schedule TO as Exhibits (a)(1)(A) and (a)(1)(B), respectively, and the Letter of Transmittal together with the Offer to Purchase constitute the “Offer”.

          Except as otherwise set forth below, the information set forth in the Schedule TO remains unchanged and is incorporated herein by reference as relevant to items in this Amendment No. 9. Capitalized terms used but not otherwise defined herein have the meanings ascribed to such terms in the Schedule TO and the related exhibits incorporated therein by reference. 

          This Amendment No. 9 is being filed to amend and supplement Item 11 and Item 12 of the Schedule TO as reflected below.

Item 11. Additional Information.

          The information set forth in the section of the Offer to Purchase entitled “Section 16—Certain Legal Matters; Regulatory Approvals” is hereby amended and supplemented by adding the following to the end of the subsection “Antitrust”:

          “On September 29, 2011, Parent announced that it had obtained antitrust clearance from the Autorité de la Concurrence in France. As previously disclosed, Parent obtained antitrust clearance from the Federal Cartel Office in Germany on September 9, 2011. The Offer remains subject to antitrust clearance in the United States.”

          The press release announcing the receipt of antitrust clearance from the Autorité de la Concurrence is attached hereto as Exhibit (a)(5)(Q) and is incorporated herein by reference.

Item 12 Exhibits.

          Item 12 of the Schedule TO is amended and supplemented by adding the following exhibits:

Exhibit No.	Description
(a)(5)(Q)	Press Release issued by Lonza Group Ltd., dated September 29, 2011

SIGNATURES

          After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: September 29, 2011
	LG Acquisition Corp.
	By:	/s/ Joseph R. Colleluori
	Name:	Joseph R. Colleluori
	Title:	S.V.P. Corp. Development
	Lonza Group Ltd.
	By:	/s/ Marc Funk
	Name:	Marc Funk
	Title:	Group General Counsel
	By:	/s/ Joseph R. Colleluori
	Name:	Joseph R. Colleluori
	Title:	S.V.P. Corp. Development

EXHIBIT INDEX

Exhibit No.	Description
(a)(1)(A)	Offer to Purchase, dated July 15, 2011, incorporated herein by reference to Exhibit (a)(1)(A) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(B)	Form of Letter of Transmittal, incorporated herein by reference to Exhibit (a)(1)(B) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(C)	Form of Notice of Guaranteed Delivery, incorporated herein by reference to Exhibit (a)(1)(C) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(D)	Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees, incorporated herein by reference to Exhibit (a)(1)(D) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(E)	Form of Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust Companies and Other Nominees, incorporated herein by reference to Exhibit (a)(1)(E) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(F)	Form of Summary Advertisement as published in The Wall Street Journal on July 15, 2011, incorporated herein by reference to Exhibit (a)(1)(E) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(G)	Form of Notice to Participants in the Arch Chemicals, Inc. Contribution Employee Ownership Plan, incorporated herein by reference to Exhibit (a)(1)(G) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(H)	Form of Instruction Form for Participants in the Arch Chemicals, Inc. Contribution Employee Ownership Plan, incorporated herein by reference to Exhibit (a)(1)(H) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(1)(I)	Form of Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9, incorporated herein by reference to Exhibit (a)(1)(I) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(2)	The Solicitation/Recommendation Statement on Schedule 14D−9 of Arch Chemicals, Inc. filed July 15, 2011, incorporated herein by reference
(a)(3)	Not applicable
(a)(4)	Not applicable
(a)(5)(A)	Joint Press Release issued by Lonza Group Ltd. and Arch Chemicals, Inc., dated July 11, 2011, incorporated herein by reference to Exhibit (a)(5)(A) to the Schedule TO of LG Acquisition Corp. filed July 11, 2011.
(a)(5)(B)	Presentation to Investors, dated July 11, 2011, incorporated herein by reference to Exhibit (a)(5)(B) to the Schedule TO of LG Acquisition Corp. filed July 11, 2011
(a)(5)(C)	Transcript of Analyst Conference Call, incorporated herein by reference to Exhibit (a)(5)(C) to the Schedule TO of LG Acquisition Corp. filed July 12, 2011
(a)(5)(D)	Transcript of Analyst Conference Call, incorporated herein by reference to Exhibit (a)(5)(D) to the Schedule TO of LG Acquisition Corp. filed July 12, 2011
(a)(5)(E)	FAQ for Customers, incorporated herein by reference to Exhibit (a)(5)(E) to the Schedule TO of LG Acquisition Corp. filed July 12, 2011
(a)(5)(F)	FAQ for Suppliers, incorporated herein by reference to Exhibit (a)(5)(F) to the Schedule TO of LG Acquisition Corp. filed July 12, 2011
(a)(5)(G)	Transcript of Media Conference Call, incorporated by reference to Exhibit (a)(5)(G) to Schedule TO of LG Acquisition Corp. filed July 13, 2011
(a)(5)(H)	Transcript of Media Conference Call, incorporated by reference to Exhibit (a)(5)(H) to Schedule TO of LG Acquisition Corp. filed July 13, 2011
(a)(5)(I)	Joint Press Release issued by Lonza Group Ltd. and Arch Chemicals, Inc., dated July 15, 2011, incorporated herein by reference to Exhibit (a)(5)(I) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(a)(5)(J)	Press Release issued by Lonza Group Ltd., dated July 27, 2011, incorporated herein by reference to Exhibit (a)(5)(J) to Amendment No. 2 to Schedule TO of LG Acquisition Corp. filed July 27, 2011

Exhibit No.	Description
(a)(5)(K)	Lonza Half-Year Report 2011, dated July 27, 2011, incorporated herein by reference to Exhibit (a)(5)(K) to Amendment No. 2 to Schedule TO of LG Acquisition Corp. filed July 27, 2011
(a)(5)(L)	Lonza Half-Year Results Presentation to Investors, dated July 27, 2011, incorporated herein by reference to Exhibit (a)(5)(L) to Amendment No. 2 to Schedule TO of LG Acquisition Corp. filed July 27, 2011
(a)(5)(M)	Transcript of Half-Year Results Newswires Conference Call, incorporated herein by reference to Exhibit (a)(5)(M) to Amendment No. 3 to Schedule TO of LG Acquisition Corp. filed July 29, 2011
(a)(5)(N)	Transcript of Half-Year Results Analyst Conference Call, incorporated herein by reference to Exhibit (a)(5)(N) to Amendment No. 3 to Schedule TO of LG Acquisition Corp. filed July 29, 2011
(a)(5)(O)	Press Release issued by Lonza Group Ltd., dated August 11, 2011, incorporated herein by reference to Exhibit (a)(5)(O) to Amendment No. 5 to Schedule TO of LG Acquisition Corp. filed August 11, 2011
(a)(5)(P)	Press Release issued by Lonza Group Ltd., dated September 12, 2011, incorporated herein by reference to Exhibit (a)(5)(P) to the Schedule TO of LG Acquisition Corp. filed September 12, 2011.
(a)(5)(Q)	Press Release issued by Lonza Group Ltd., dated September 29, 2011*
(b)(1)	Mandate Letter, dated as of July 10, 2011, by and among Lonza Group Ltd. and the Initial Banks named therein, incorporated herein by reference to Exhibit (b)(1) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(b)(2)	Ancillary Letter, dated as of July 13, 2011, by and among Lonza Group Ltd. and the Initial Banks named therein, incorporated herein by reference to Exhibit (b)(2) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(b)(3)	Multicurrency Term and Revolving Facilities Agreement, dated as of September 9, 2011, by and among Lonza Group Ltd.; certain subsidiaries of Lonza Group Ltd.; Citigroup Global Markets Limited, Credit Suisse AG and J.P. Morgan Limited, as mandated lead arrangers; Credit Suisse AG, London Branch as agent; and the financial institutions named therein as lenders, incorporated herein by reference to Exhibit (b)(3) to the Schedule TO of LG Acquisition Corp. filed September 12, 2011.
(d)(1)	Agreement and Plan of Merger, dated as of July 10, 2011, by and among Lonza Group Ltd., LG Acquisition Corp. and Arch Chemicals, Inc., incorporated herein by reference to Exhibit 2.1 to the Current Report on Form 8-K of Arch Chemicals, Inc. filed July 11, 2011
(d)(2)	Confidentiality Agreement, dated as of May 2, 2011, between Lonza Group Ltd. and Arch Chemicals, Inc., incorporated herein by reference to Exhibit (d)(2) to the Schedule TO of LG Acquisition Corp. filed July 15, 2011.
(g)	Not applicable
(h)	Not applicable

* Filed herewith.

EX-99.(A)(5)(Q)

Exhibit (a)(5)(Q)

Corporate
	Lonza Group Ltd
	Muenchensteinerstrasse 38
	4002 Basel, Switzerland
	www.lonza.com
News release

Lonza receives antitrust clearance in France

Basel, Switzerland, 29 September 2011 – Lonza Group Ltd (SIX: LONN), one of the world’s leading suppliers to the life science industries, announced today that it has obtained antitrust clearance from the Autorité de la Concurrence in France for its tender offer, through its wholly owned subsidiary LG Acquisition Corp., for 100 percent of the outstanding shares of common stock of Arch Chemicals, Inc. (NYSE:ARJ).

The tender offer is at a price of USD 47.20 per share in cash, without interest and less any required withholding taxes pursuant to a previously announced merger agreement, dated 10 July 2011, by and among Arch Chemicals, Lonza and LG Acquisition Corp.

The tender offer remains subject to antitrust clearance in the United States. The tender offer has previously been extended to 30 September 2011.

The tender offer may be further extended if conditions to the tender offer remain unsatisfied. Any additional extension of the tender offer will be followed as promptly as practicable by public announcement thereof, and such announcement will be made no later than 9:00 a.m. New York City time on the next business day after the previously scheduled expiration date. The closing of the tender offer is subject to customary terms and conditions, including antitrust clearances and the tender of more than two-thirds of Arch Chemicals’ outstanding shares of common stock.

About Lonza

Lonza is one of the world’s leading suppliers to the pharmaceutical, healthcare and life science industries. Products and services span its customers’ needs from research to final product manufacture. It is the global leader in the production and support of active pharmaceutical ingredients both chemically as well as biotechnologically. Biopharmaceuticals are one of the key growth drivers of the pharmaceutical and biotechnology industries. Lonza has strong capabilities in large and small molecules, peptides, amino acids and niche bioproducts which play an important role in the development of novel medicines and healthcare products. In addition, Lonza is a leader in cell-based research, endotoxin detection and cell therapy manufacturing. Furthermore, the company is a leading provider of value chemical and biotech ingredients to the nutrition, hygiene, preservation, agro and personal care markets.

Corporate
	Lonza Group Ltd
	Muenchensteinerstrasse 38
	4002 Basel, Switzerland
	www.lonza.com
News release

Lonza is headquartered in Basel, Switzerland and is listed on the SIX Swiss Exchange. In 2010, the company had sales of CHF 2.680 billion. Further information can be found at www.lonza.com.

Further Information

Lonza Group Ltd	Lonza Group Ltd	Lonza Group Ltd
Head of Corporate Communications	Investor Relations	Media Relations
Dominik Werner	Dirk Oehlers	Melanie Disa
Tel +41 61 316 8798	Tel +41 61 316 8540	Tel +1 201 316 9413
Fax +41 61 316 9798	Fax +41 61 316 9540	Fax +1 201 696 3533
dominik.werner@lonza.com	dirk.oehlers@lonza.com	melanie.disa@lonza.com

Forward-looking statements

Forward-looking statements contained herein are qualified in their entirety as there are certain factors that could cause results to differ materially from those anticipated. Any statements contained herein that are not statements of historical fact (including statements containing the words “believes,” “plans,” “anticipates,” “expects,” “estimates” and similar expressions) should be considered to be forward-looking statements. Statements herein regarding the proposed transaction between Lonza and Arch Chemicals, the expected timetable for completing the transaction, the potential benefits of the transaction, and any other statements about management’s future expectations, beliefs, goals, plans or prospects also constitute forward-looking statements. Investors are cautioned that all forward-looking statements involve risks and uncertainty. There are a number of important factors that could cause actual results or events to differ materially from those indicated by such forward-looking statements, including: uncertainties as to the timing of the tender offer and merger; uncertainties as to how many shareholders will tender their stock in the offer; the possibility that various closing conditions for the transaction may not be satisfied or waived; the effects of disruption from the transaction making it more difficult to maintain relationships with employees, customers, and other business partners; and changes in the political, social and regulatory framework in which the company operates, or in economic or technological trends or conditions, including currency fluctuations, inflation and consumer confidence, on a global, regional or national basis. Except as otherwise required by law, Lonza disclaims any intention or obligation to update any forward-looking statements as a result of developments occurring after this communication was made.

Additional information

This communication is for informational purposes only and is not a recommendation, an offer to purchase or a solicitation of an offer to sell shares of Arch Chemicals. LG Acquisition Corp., Lonza’s indirect wholly owned subsidiary, has filed a tender offer statement on Schedule TO with the U.S. Securities and Exchange Commission, and Arch Chemicals has filed a solicitation/recommendation statement on Schedule 14D-9 with respect to the tender offer.

Corporate
	Lonza Group Ltd
	Muenchensteinerstrasse 38
	4002 Basel, Switzerland
	www.lonza.com
News release

Investors and Arch Chemicals shareholders are strongly advised to carefully read the tender offer statement (including the offer to purchase, the letter of transmittal and the related tender offer documents) and the related solicitation/recommendation statement, as well as any amendments thereto and other relevant documents filed with the SEC when they become available, because they will contain important information. Investors and Arch Chemicals shareholders may obtain a free copy of the tender offer statement, the solicitation/recommendation statement and other documents (when available) filed with the SEC at the SEC’s website at www.sec.gov. The tender offer statement and other documents that LG Acquisition Corp. files with the SEC may also be obtained free of charge by directing a request by mail to MacKenzie Partners, Inc. at 105 Madison Avenue, New York, New York 10016, by calling toll-free at +1 800 322 2885 or by email to tenderoffer@mackenziepartners.com.