================================================================================ SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K/A AMENDMENT NO. 1 TO FORM 10-K FOR ANNUAL AND TRANSITION REPORTS PURSUANT TO SECTIONS 13 OR 15(d) OF THE SECURITIES ACT OF 1934 (Mark One) [X] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 1998 OR [_] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-14601 Arch Chemicals, Inc. (Exact name of registrant as specified in its charter) Virginia 06-1526315 (State or other jurisdiction of (I.R.S. Employer Identification No.) incorporation or organization) 501 Merritt 7 Norwalk, CT 06856 (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code: (203) 229-2900 Securities registered pursuant to Section 12(b) of the Act: Name of each exchange Title of each class on which registered --------------------- -------------------- Common Stock New York Stock Exchange Series A Participating Cumulative New York Stock Exchange Preferred Stock Purchase Rights Securities registered pursuant to Section 12(g) of the Act: None ================================================================================ EXPLANATORY NOTE REGARDING AMENDMENT NO. 1: This Amendment No. 1 is being filed solely to file an amended Exhibit 27 - Financial Data Schedule so as to add the multiplier tag to the Financial Data Schedule previously filed as Exhibit 27 in the Form 10-K of Arch Chemicals, Inc. for the year ended December 31, 1998. The list of exhibits contained in "Item 14(a)3 Exhibits" to such previously filed Form 10-K is also amended to replace "27. Financial Data Schedule" with "27. Amended and Restated Financial Data Schedule." SIGNATURES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. ARCH CHEMICALS, INC. Date: June 3, 1999 By Louis S. Massimo ---------------- Louis S. Massimo Vice President and Chief Financial Officer