MASTEC INC

Shareholders and Board of Directors

Coral Gables, Florida

Opinion on Internal Control over Financial Reporting

We have audited MasTec, Inc.’s (the “Company’s”) internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (the “COSO criteria”). In our opinion, based on our audit and the report of the other auditors, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2023, based on the COSO criteria.

We did not examine the effectiveness of internal control over financial reporting of IEA Energy Services, LLC and subsidiaries (“IEA LLC”), a wholly-owned subsidiary of the Company, whose financial statements reflect total assets and revenue constituting 7.3% and 14.4%, respectively, of the related consolidated financial statement amounts as of and for the year ended December 31, 2023. IEA LLC’s internal control over financial reporting was audited by other auditors whose report has been furnished to us, and our opinion, insofar as it relates to the effectiveness of IEA LLC’s internal control over financial reporting, is based solely on the report of the other auditors.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the consolidated balance sheets of the Company as of December 31, 2023 and 2022, the related consolidated statements of operations, comprehensive income, equity, and cash flows for each of the three years in the period ended December 31, 2023, and the related notes and schedule (collectively referred to as “the financial statements”) and our report dated February 29, 2024 expressed an unqualified opinion thereon.

Basis for Opinion

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Item 9A, Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit of internal control over financial reporting in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit 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 audit also included performing such other procedures as we considered necessary in the circumstances. We believe that our audit and the report of the other auditors provide a reasonable basis for our opinion.

As indicated in the accompanying “Item 9A, Management’s Report on Internal Control over Financial Reporting”, management’s assessment of and conclusion on the effectiveness of internal control over financial reporting did not include the internal controls of two entities acquired in 2023, which are included in the consolidated balance sheet of the Company as of December 31, 2023, and the related consolidated statements of operations, comprehensive income, equity, and cash flows for the year then ended. These two entities constituted approximately 2% of total assets as of December 31, 2023, and approximately 1% of revenues for the year then ended. Management did not assess the effectiveness of internal control over financial reporting of these acquired entities because of the timing of their acquisitions. Our audit of internal control over financial reporting of the Company also did not include an evaluation of the internal control over financial reporting of these acquired entities.

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 (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) 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 (3) 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.

/s/BDO USA, P.C.

Miami, Florida