1 SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 ---------------------------------- FORM 10-K/A AMENDMENT NO. 1 [X] ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended September 30, 1998 OR [ ] TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period ________ to ________ Commission file number: 1-10596 ESCO Electronics Corporation (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER) Missouri 43-1554045 (STATE OR OTHER JURISDICTION (I.R.S. EMPLOYER OF INCORPORATION OR ORGANIZATION) IDENTIFICATION NO.) 8888 Ladue Road, Ste. 200 St. Louis, Missouri 63124-2090 (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES) (ZIP CODE) REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE: (314) 213-7200 SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE ACT: Name of Each Exchange on Title of Each Class Which Registered ------------------- ---------------- Common Stock Trust Receipts New York Stock Exchange, Inc. Common Stock, par value $0.01 per New York Stock share Exchange, Inc. Preferred Stock Purchase Rights New York Stock Exchange, Inc. (Cover page 1 of 2 pages)

2 SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE ACT: None Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to filing requirements for the past 90 days. Yes X No Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form l0-K or any amendment to this Form l0-K. [X] Aggregate market value of the Common Stock Trust Receipts held by non-affiliates of the registrant as of close of business on December 18, 1998: $104,266,488.* * For purpose of this calculation only, without determining whether the following are affiliates of the registrant, the registrant has assumed that (i) its directors and executive officers are affiliates, and (ii) no party who has filed a Schedule 13D or 13G is an affiliate. Number of Common Stock Trust Receipts outstanding at December 18, 1998: 12,267,321 Receipts. DOCUMENTS INCORPORATED BY REFERENCE: 1. Portions of the registrant's Annual Report to Stockholders for fiscal year ended September 30, 1998 (the "1998 Annual Report") (Parts I and II). 2. Portions of the registrant's Proxy Statement dated December 4, 1998 (Part III). (Cover page 2 of 2 pages)

3 PART II ITEM 5. MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS. On July 1 and August 17, 1998, ESCO issued a total of 451,020 Common Stock Trust Receipts pursuant to Rule 506 under the Securities Act of 1933, as amended, to the shareholders of Advanced Membrane Technology, Inc. (renamed PTI Advanced Filtration Inc.) as partial consideration for the acquisition of all of the capital stock of that company. See Note 2 of the Notes to Consolidated Financial Statements in the 1998 Annual Report. Other information required by this item is incorporated herein by reference to Notes 7 and 8 of the Notes to Consolidated Financial Statements, "Common Stock Market Prices" and "Shareholders' Summary--Capital Stock Information" appearing in the 1998 Annual Report. A special cash distribution of $3.00 per share was paid to Stockholders in September 1996. No other cash dividends have been declared on the Common Stock underlying the Receipts, and ESCO does not anticipate, currently or in the foreseeable future, paying cash dividends on the Common Stock, although it reserves the right to do so to the extent permitted by applicable law and agreements. ESCO's dividend policy will be reviewed by the Board of Directors at such future time as may be appropriate in light of relevant factors at that time, based on ESCO's earnings and financial position and such other business considerations as the Board deems relevant at that time. SIGNATURES Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. ESCO ELECTRONICS CORPORATION By: /s/ D.J. Moore ---------------------- D.J. Moore Chairman, President and Chief Executive Officer Dated August 12, 1999