X0202 SCHEDULE 13D/A 0000868857 XXXXXXXX LIVE 3 Common stock, par value $0.01 per share 08/10/2026 false 0001887944 82455M109 Shimmick Corp

530 TECHNOLOGY DRIVE SUITE 300 IRVINE CA 92618

David Y. Gan (213) 593-8000 EVP, Chief Legal Officer AECOM, 300 South Grand Avenue Los Angeles CA 90071 0000868857 N AECOM b OO N DE 7745000.00 0.00 7745000.00 0.00 7745000.00 N 18.7 CO The amounts in rows 7, 9 and 11 and the percentage in row 13 include (i) 6,708,051 shares of the Shimmick Corporation's (the "Issuer") common stock, par value $0.01 per share ("Common Stock"), directly held by the Reporting Person and (ii) 1,036,949 additional shares of Common Stock of which the Reporting Person may acquire voting and dispositive power within 60 days hereof pursuant to the terms of the Escrow Services Agreement dated June 24, 2024, by and among the Issuer, the Reporting Person and Equiniti Trust Company, LLC. Common stock, par value $0.01 per share Shimmick Corp 530 TECHNOLOGY DRIVE SUITE 300 IRVINE CA 92618 This Amendment No. 3 ("Amendment No. 3") to Schedule 13D amends and supplements the initial statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") by the Reporting Person on May 24, 2024 (as amended prior to the filing of this Amendment No. 3, the "Schedule 13D"). This Amendment No. 3 is being filed to reflect a change in the percentage of the Common Stock owned by the Reporting Person as a result of a change in the number of shares of Common Stock outstanding and to update Schedule 1. Capitalized terms used but not defined in this Amendment No. 3 shall have the same meanings ascribed to them in the Schedule 13D. Item 2 (c) of the Schedule 13D is hereby amended and restated to read as follows: (c) The principal business of the Reporting Person is providing professional infrastructure consulting services for governments, businesses and organizations. The directors and executive officers of the Reporting Person are listed on Schedule I attached hereto, which is incorporated herein by reference into this Item 2 ("Schedule 1"). Items 5(a) of the Schedule 13D is hereby amended and restated to read as follows: (a) The information set forth in Items 7-13 of the cover page is hereby incorporated by reference into this Item 5(a). The percentage calculations herein are based upon 41,335,823 shares of Common Stock issued and outstanding as of August 7, 2026, as reported in the Issuer's Quarterly Report on Form 10-Q, filed with the SEC on August 10, 2026. Item 5(b) of the Schedule 13D is hereby amended and restated to read as follows: (b) The information set forth in Items 7-13 of the cover page is hereby incorporated by reference into this Item 5(b) . AECOM /s/ David Y. Gan 08/12/2026