Note 1. Basis of presentation

The interim unaudited Condensed Consolidated Financial Statements of Mayville Engineering Company, Inc. and subsidiaries (MEC, the Company, we, our, us or similar terms) presented here have been prepared in accordance with the accounting principles generally accepted in the United States of America (GAAP) and with instructions to Form 10-Q and Article 10 of Regulation S-X. They reflect all adjustments which are, in the opinion of management, necessary for a fair presentation of the results of operations and financial position for the interim unaudited periods presented. All intercompany balances and transactions have been eliminated in consolidation.

Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted. These interim unaudited Condensed Consolidated Financial Statements should be read in conjunction with the Company’s consolidated financial statements and notes thereto for the year ended December 31, 2024, included in the Company’s Annual Report on Form 10-K. A summary of the Company’s significant accounting policies is included in the Company’s 2024 financial statements in the Annual Report on Form 10-K. The Company followed these policies in preparation of the interim unaudited Condensed Consolidated Financial Statements except for new accounting pronouncements adopted as described below.

Nature of Operations

MEC is a leading U.S.-based, vertically-integrated, value-added manufacturing partner providing a full suite of manufacturing solutions from concept to production, including design, prototyping and tooling, fabrication, aluminum extrusion, coating, assembly and aftermarket components. Our customers operate in diverse end markets, including heavy- and medium-duty commercial vehicles, construction & access equipment, powersports, agriculture, military and other end markets. Founded in 1945 and headquartered in Milwaukee, Wisconsin, we are a leading Tier I U.S. supplier of highly engineered components to original equipment manufacturer (OEM) customers with leading positions in their respective markets. The Company operates 27 facilities, of which 26 are in operation, located in Arkansas, Illinois, North Carolina, Michigan, Mississippi, Ohio, Pennsylvania, Virginia, and Wisconsin. In connection with the acquisition of Accu-Fab, LLC (Accu-Fab), as discussed in Note 18 – Subsequent Events, four facilities were added which were located in Illinois and North Carolina. Our engineering expertise and technical know-how allow us to add value through every product redevelopment cycle (generally every three to five years for our customers).

Our one operating segment focuses on producing metal components that are used in a broad range of heavy- and medium-duty commercial vehicles, construction & access equipment, powersports, agricultural, military and other products.

Recent Accounting Pronouncements

In November 2024, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2024-03, Expense Disaggregation Disclosures, amending Accounting Standards Codification (ASC) 220, Income Statement – Reporting Comprehensive Income. The amendment requires an entity to provide a disclosure within the financial statement footnotes showing the disaggregation of certain expenses included in relevant expense captions on the consolidated income statement, with a qualitative description of the amounts that are not separately disaggregated quantitatively. The guidance also requires disclosure of the total amount of selling expenses and, in annual reporting periods, an entity’s definition of selling expenses. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026 and for interim periods beginning after December 15, 2027. The guidance is applied on a prospective basis, with a retrospective option and allows for early adoption. The Company is evaluating the potential impact of this guidance on the consolidated financial statements.

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures, amending ASC 740, Income Taxes. The amendment is intended to enhance the transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. The amendments require that on an annual basis, entities disclose specific categories in the rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. In addition, the amendments require that entities disclose additional information about income taxes paid as well as additional disclosures of pretax income and income tax expense and remove the requirement to disclose certain items that are

no longer considered cost beneficial or relevant. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024, with early adoption permitted. We believe this standard will expand our disclosures but will not have a material impact on our consolidated financial statements. We will adopt this standard in the fourth quarter of 2025.