Knife River Corp

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the stockholder and the Board of Directors of Knife River Corporation

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Knife River Corporation and Subsidiaries (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 (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements 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 audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the 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 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 financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the 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 from Contracts with Customers—Contracting Services Revenue—Refer to Notes 1, 2 3 and 4 to the financial statements

Critical Audit Matter Description

The Company recognizes contracting services revenue over time using an input method based on the cost-to-cost measure of progress for contracts because it best depicts the transfer of assets to the customer which occurs as Knife River incurs costs on the contract. Under the cost-to-cost measure of progress, the costs incurred are compared with total estimated costs of a performance obligation. Revenues are recorded proportionately to the costs incurred. This method depends largely on the ability to make reasonably dependable estimates related to the extent of progress toward completion of the contract, contract revenues, contract costs. The accounting for these contracts involves judgment, particularly as it relates to the process of estimating total costs and profit for the performance obligation. For the year ended December 31, 2023, the Company recognized $1.3 billion of contracting services revenue.

Given the judgments necessary to estimate total costs and profit for the performance obligations used to recognize revenue for construction contracts, auditing such estimates required extensive audit effort due to the volume and complexity of construction contracts and a high degree of auditor judgment when performing audit procedures and evaluating the results of those procedures.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to management’s estimates of total costs and profit for the performance obligations used to recognize revenue for contracts included the following, among others:

•We tested the operating effectiveness of management’s controls over contracting services revenue, including controls over management’s estimation of total costs and profit for the performance obligations.

•We developed an expectation of the amount of contracting services revenue for certain performance obligations based on prior year markups, and taking into account current year events, applied to the contracting services contract costs in the current year and compared our expectation to the amount of contracting services revenue recorded by management.

•We selected a sample of contracting services contracts and performed the following:

–Evaluated whether the contracts were properly included in management’s calculation of contracting services revenue based on the terms and conditions of each contract, including whether continuous transfer of control to the customer occurred as progress was made toward fulfilling the performance obligation.

–Compared the transaction prices to the consideration expected to be received based on current rights and obligations under the contracts and any modifications that were agreed upon with the customers.

–Tested management’s identification of distinct performance obligations by evaluating whether the underlying goods and services were highly interdependent and interrelated.

–Tested the accuracy and completeness of the costs incurred to date for the performance obligation.

–Evaluated the estimates of total cost and profit for the performance obligation by:

◦Comparing total costs incurred to date to the costs management estimated to be incurred to date and selecting specific cost types to compare costs incurred to date to management’s estimated costs at completion.

◦Evaluating management’s ability to achieve the estimates of total cost and profit by performing corroborating inquiries with the Company’s project managers and engineers, and comparing the estimates to management’s work plans, engineering specifications, and supplier contracts.

◦Comparing management’s estimates for the selected contracts to costs and profits of similar performance obligations, when applicable.

–Tested the mathematical accuracy of management’s calculation of contracting services revenue for the performance obligation.

•We evaluated management’s ability to estimate total costs and profits accurately by comparing actual costs and profits to management’s historical estimates for performance obligations that have been fulfilled.

/s/Deloitte & Touche LLP

Minneapolis, Minnesota

February 27, 2024

We have served as the Company's auditor since 2002.