PLEXUS CORP

Disclosure Controls and Procedures

The Company maintains disclosure controls and procedures designed to ensure that the information the Company must disclose in its filings with the Securities and Exchange Commission ("SEC") is recorded, processed, summarized and reported on a timely basis. The Company’s President and Chief Executive Officer ("CEO") and Chief Financial Officer ("CFO") have reviewed and evaluated, with the participation of the Company’s management, the Company’s disclosure controls and procedures as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the "Exchange Act") as of the end of the period covered by this report. Based on such evaluation, the CEO and CFO have concluded that, as of September 27, 2025, the Company’s disclosure controls and procedures are effective, at the reasonable assurance level, (a) in recording, processing, summarizing and reporting, on a timely basis, information required to be disclosed by the Company in the reports the Company files or submits under the Exchange Act, and (b) in assuring that information is accumulated and communicated to the Company’s management, including the CEO and CFO, as appropriate to allow timely decisions regarding required disclosure.

Management’s Annual Report on Internal Control Over Financial Reporting

Management of the Company is responsible for establishing and maintaining adequate internal control over financial reporting, as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f). Management of the Company, including its CEO and CFO, has assessed the effectiveness of its internal control over financial reporting as of September 27, 2025, based on the criteria established in "Internal Control - Integrated Framework" issued by the Committee of Sponsoring Organizations of the Treadway Commission ("COSO") (2013). Based on its assessment and those criteria, management has reached the conclusion that the Company's internal control over financial reporting was effective as of September 27, 2025.

The independent registered public accounting firm of PricewaterhouseCoopers LLP has audited the Company’s internal control over financial reporting as of September 27, 2025, as stated in its report included herein.

Changes in Internal Control Over Financial Reporting

There have been no changes in the Company’s internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) that occurred during the Company’s most recent fiscal quarter that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

Limitations on the Effectiveness of Controls

Our management, including our CEO and CFO, does not expect that our disclosure controls and internal controls will prevent all errors and all fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. Further, the design of a control system must reflect the fact that there are resource constraints, and the benefits of controls must be considered relative to their costs. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues and instances of fraud, if any, within the Company have been detected. These inherent limitations include the realities that judgments in decision-making can be faulty, and that breakdowns can occur because of simple errors or mistakes. Additionally, controls can be circumvented by the individual acts of some persons, by collusion of two or more people, or by management override of the control. The design of any system of controls also is based in part upon certain assumptions about the likelihood of future events, and there can be no assurance that any design will succeed in achieving its stated goals under all potential future conditions; over time, a control may become inadequate because of changes in conditions, or the degree of compliance with the policies or procedures may deteriorate. Because of the inherent limitations in a cost-effective control system, misstatements due to error or fraud may occur and not be detected. Notwithstanding the foregoing limitations on the effectiveness of controls, we have nonetheless reached the conclusion that the Company's disclosure controls and procedures and internal control over financial reporting were effective as of September 27, 2025.