PLEXUS CORP

Report of Independent Registered Public Accounting Firm

To the Board of Directors and Shareholders of Plexus Corp.

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated balance sheets of Plexus Corp. and its subsidiaries (the “Company”) as of September 27, 2025 and September 28, 2024, and the related consolidated statements of comprehensive income, of shareholders' equity and of cash flows for each of the three years in the period ended September 27, 2025, including the related notes and financial statement schedule listed in the accompanying index (collectively referred to as the "consolidated financial statements"). We also have audited the Company's internal control over financial reporting as of September 27, 2025, based on criteria established in Internal Control - Integrated Framework(2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of September 27, 2025 and September 28, 2024, and the results of its operations and its cash flows for each of the three years in the period ended September 27, 2025 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of September 27, 2025, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.

Basis for Opinions

The Company's management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in Management’s Annual Report on Internal Control Over Financial Reporting appearing under Item 9A. Our responsibility is to express opinions on the Company’s consolidated financial statements and on the Company's internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

Definition and Limitations of Internal Control over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Critical Audit Matters

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that (i) relates to accounts or disclosures that are material to the consolidated financial statements and (ii) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Revenue Recognition

As described in Notes 1 and 15 to the consolidated financial statements, the Company's net sales were $4.0 billion for the year ended September 27, 2025. The Company's revenue is recognized over time for arrangements with customers for which: (i) the Company's performance does not create an asset with an alternative use to the Company, and (ii) the Company has an enforceable right to payment, including reasonable profit margin, for performance completed to date. Revenue recognized over time is estimated based on costs incurred to date plus a reasonable profit margin. If either of the two conditions are not met to recognize revenue over time, revenue is recognized following the transfer of control of such products to the customer, which typically occurs upon shipment or delivery depending on the terms of the underlying arrangement.

The principal consideration for our determination that performing procedures relating to revenue recognition is a critical audit matter is a high degree of auditor effort in performing procedures related to the Company's revenue recognition.

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the revenue recognition process. These procedures also included, among others (i) testing the completeness, accuracy, and occurrence of revenue recognized for a sample of revenue transactions by obtaining and inspecting source documents, such as purchase orders, invoices, proof of shipment, and cash receipts; (ii) confirming a sample of outstanding customer invoice balances as of September 27, 2025, and for confirmations not returned, obtaining and inspecting source documents, such as purchase orders, invoices, proof of shipment, and subsequent cash receipts; (iii) testing the accuracy and timing of revenue recognized as of period end for a sample of arrangements with customers that meet the conditions for over time revenue recognition by obtaining and inspecting source documents, such as master services agreements, purchase orders, inventory balances as of period end, and estimated profit margin support which includes historical results; and (iv) testing the completeness and accuracy of the data used by management to calculate the revenue recognized over time.

/s/PricewaterhouseCoopers LLP

Milwaukee, Wisconsin

November 14, 2025

We have served as the Company’s auditor since at least 1985. We have not been able to determine the specific year we began serving as auditor of the Company.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(in thousands, except per share data)