# EDGAR Filing Document

**Accession Number:** 0001955520
**File Stem:** 0001628280-26-043977
**Filing Date:** 2026-6
**Character Count:** 44476
**Document Hash:** e567364569dc92d21c5832e325c12339
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-26-043977.hdr.sgml**: 20260617

**ACCESSION NUMBER**: 0001628280-26-043977

**CONFORMED SUBMISSION TYPE**: 11-K

**PUBLIC DOCUMENT COUNT**: 37

**CONFORMED PERIOD OF REPORT**: 20251231

**FILED AS OF DATE**: 20260617

**DATE AS OF CHANGE**: 20260617

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Knife River Corp
- **CENTRAL INDEX KEY:** 0001955520
- **STANDARD INDUSTRIAL CLASSIFICATION:** MINING, QUARRYING OF NONMETALLIC MINERALS (NO FUELS) [1400]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 921008893
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 11-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-41642
- **FILM NUMBER:** 261099247

**BUSINESS ADDRESS:**
- **STREET 1:** 1150 W. CENTURY AVE,
- **CITY:** BISMARCK
- **STATE:** ND
- **ZIP:** 58503
- **BUSINESS PHONE:** 701-530-1400

**MAIL ADDRESS:**
- **STREET 1:** 1150 WEST CENTURY AVENUE
- **CITY:** BISMARCK
- **STATE:** ND
- **ZIP:** 58503

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Knife River Holding Co
- **DATE OF NAME CHANGE:** 20221121

?xml version='1.0' encoding='ASCII'? knf-20260617

**UNITED STATES SECURITIES AND EXCHANGE COMMISSION**

**WASHINGTON, D.C. 20549**

**FORM 11-K**

🗷 ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2025

OR

□ TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from ______________ to ________________

Commission file number 1-41642

**KNIFE RIVER CORPORATION**

**401(k) RETIREMENT PLAN**

(Full title of the plan)

**Knife River Corporation**

(Name of issuer of securities held pursuant to the plan)

KNIFE RIVER CORPORATION

1150 WEST CENTURY AVENUE

P.O. BOX 5568

BISMARCK, NORTH DAKOTA 58506-5568

(Address of the plan and address of the issuer's principal executive offices)

------

**<u>CONTENTS</u>**

---

| | |
|:---|:---|
| **Required Information** | **Page** |
| &nbsp;&nbsp;&nbsp;<u>[Report of Independent Registered Public Accounting Firm](#i864c9ea6d95545a38a13aaaa3a03dc96_7)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[1](#i864c9ea6d95545a38a13aaaa3a03dc96_7)</u> |
| &nbsp;&nbsp;&nbsp;**Financial Statements:** |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<u>[Statements of Net Assets Available for Benefits - December 31, 2025 and 2024](#i864c9ea6d95545a38a13aaaa3a03dc96_10)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[2](#i864c9ea6d95545a38a13aaaa3a03dc96_10)</u> |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<u>[Statement of Changes in Net Assets Available for Benefits - Year Ended December 31, 2025](#i864c9ea6d95545a38a13aaaa3a03dc96_13)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[3](#i864c9ea6d95545a38a13aaaa3a03dc96_13)</u> |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<u>[Notes to Financial Statements](#i864c9ea6d95545a38a13aaaa3a03dc96_16)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[4](#i864c9ea6d95545a38a13aaaa3a03dc96_16)</u> |
| &nbsp;&nbsp;&nbsp;**<u>[Supplemental Schedules:](#i864c9ea6d95545a38a13aaaa3a03dc96_49)</u>** |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<u>[Schedule H, Line 4i - Schedule of Assets (Held at End of Year) as of December 31, 2025](#i864c9ea6d95545a38a13aaaa3a03dc96_55)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[11](#i864c9ea6d95545a38a13aaaa3a03dc96_55)</u> |
| &nbsp;&nbsp;&nbsp;<u>[Exhibit Index](#i864c9ea6d95545a38a13aaaa3a03dc96_58)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[12](#i864c9ea6d95545a38a13aaaa3a03dc96_58)</u> |
| &nbsp;&nbsp;&nbsp;<u>[Signature](#i864c9ea6d95545a38a13aaaa3a03dc96_61)</u> | &nbsp;&nbsp;&nbsp;&nbsp;<u>[13](#i864c9ea6d95545a38a13aaaa3a03dc96_61)</u> |
| &nbsp;&nbsp;&nbsp;Exhibit: |  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Consent of Independent Registered Public Accounting Firm |  |

---

------

Report of Independent Registered Public Accounting Firm

**Plan Administrator and Plan Participants**

**Knife River Corporation 401(k) Retirement Plan**

**Opinion on the financial statements** 

We have audited the accompanying statements of net assets available for benefits of Knife River Corporation 401(k) Retirement Plan (the "Plan") as of December 31, 2025 and 2024, the related statement of changes in net assets available for benefits for the year ended December 31, 2025, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the net assets available for benefits of the Plan as of December 31, 2025 and 2024, and the changes in net assets available for benefits for the year ended December 31, 2025 in conformity with accounting principles generally accepted in the United States of America.

**Basis for opinion** 

These financial statements are the responsibility of the Plan's management. Our responsibility is to express an opinion on the Plan'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 Plan 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 Plan 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 Plan'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.

**Supplemental information** 

The schedule of assets (held at end of year) as of December 31, 2025 ("supplemental information") has been subjected to audit procedures performed in conjunction with the audit of the Plan's financial statements. The supplemental information is the responsibility of the Plan's management. Our audit procedures included determining whether the supplemental information reconciles to the financial statements or the underlying accounting and other records, as applicable, and performing procedures to test the completeness and accuracy of the information presented in the supplemental information. In forming our opinion on the supplemental information, we evaluated whether the supplemental information, including its form and content, is presented in conformity with the Department of Labor's Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. In our opinion, the supplemental information is fairly stated, in all material respects, in relation to the financial statements as a whole.

/s/ GRANT THORNTON LLP

We have served as the Plan's auditor since 2024.

Chicago, Illinois

June 17, 2026

------

**Knife River Corporation**

**401(k) Retirement Plan**

**Statements of Net Assets Available for Benefits**

---

| | | |
|:---|:---|:---|
| December 31, | **2025** | 2024 |
| **Assets:** |  |  |
| **Investments:** |  |  |
| &nbsp;&nbsp;&nbsp;Investments at fair value (Note 4) | $**872343615** | $752734444 |
| &nbsp;&nbsp;&nbsp;Fully benefit-responsive investment contract, at contract value (Note 3) | **55863527** | 61677261 |
| **Total investments** | **928207142** | 814411705 |
| **Receivables:** |  |  |
| &nbsp;&nbsp;&nbsp;Employer contributions | **11557820** | 18879643 |
| &nbsp;&nbsp;&nbsp;Participant contributions | **—** | 550010 |
| &nbsp;&nbsp;&nbsp;Notes receivable from participants | **24723422** | 22588423 |
| &nbsp;&nbsp;&nbsp;Other receivables | **—** | 150747 |
| **Total receivables** | **36281242** | 42168823 |
| **Total assets** | **964488384** | 856580528 |
| **Liabilities:** |  |  |
| &nbsp;&nbsp;Other liabilities | **6750** |  |
| **Total liabilities** | **6750** |  |
| **Net assets available for benefits** | $**964481634** | $856580528 |

---

The accompanying notes are an integral part of these financial statements.

------

**Knife River Corporation**

**401(k) Retirement Plan**

**Statement of Changes in Net Assets Available for Benefits**

**Year ended December 31, 2025**

---

| | |
|:---|:---|
| **Additions to Net Assets Attributed to:** | |
| **Investment income:** | |
| &nbsp;&nbsp;&nbsp;Interest and dividends | $**7807562** |
| &nbsp;&nbsp;Net appreciation in fair value of investments | **81867095** |
| **Total investment income** | **89674657** |
| **Interest income on notes receivable from participants** | **1793950** |
| **Contributions:** |  |
| &nbsp;&nbsp;&nbsp;Employers | **29278160** |
| &nbsp;&nbsp;&nbsp;Participants | **45561826** |
| &nbsp;&nbsp;&nbsp;Participant rollovers | **35039836** |
| **Total contributions** | **109879822** |
| **Total additions** | **201348429** |
| **Deductions from Net Assets Attributed to:** |  |
| &nbsp;&nbsp;&nbsp;Distributions to participants | **92457299** |
| &nbsp;&nbsp;&nbsp;Administrative expenses | **990024** |
| **Total deductions** | **93447323** |
| **Net increase in net assets available for benefits** | **107901106** |
| **Net assets available for benefits at beginning of year** | **856580528** |
| **Net assets available for benefits at end of year** | $**964481634** |

---

The accompanying notes are an integral part of this financial statement.

------

**Knife River Corporation**

**401(k) Retirement Plan**

**Notes to Financial Statements**

**December 31, 2025 and 2024**

**<u>Note 1 - Description of the Plan</u>**

The following description of the Knife River Corporation 401(k) Retirement Plan (the Plan) provides only general information. Participants should refer to the Plan document for a more complete description of the Plan's provisions.

**General**

Knife River Corporation (Knife River or the Company) established the Knife River Corporation 401(k) Retirement Plan (the "Plan") effective May 1, 2023. The Plan is a defined contribution plan that is subject to the provisions of the Employee Retirement Income Security Act of 1974, as amended, (ERISA). The portion of the Plan invested primarily in the Knife River Corporation common stock is designed as an Employee Stock Ownership Plan (ESOP). The Company and any of its direct subsidiaries that participate in the Plan are the Employers (the Employers). The fiscal year of the Plan is the calendar year.

The Board of Directors of the Company may, at any time, amend or modify the Plan. The Company has delegated to the Employee Benefits Committee (the Committee) the authority to amend or modify the Plan; however, certain amendments identified in the Plan document are subject to approval by the Board of Directors of the Company.

Although it has not expressed any intent to do so, the Board of Directors of the Company has the right under the Plan to discontinue its contributions, at any time, and to terminate the Plan subject to the provisions of ERISA. The Board of Directors or governing entities of any Employer may, at any time, terminate participation in the Plan with respect to such Employer. In the event of a Plan termination, participants would become 100 percent vested in their employer contributions.

On March 7, 2025, the Company acquired Strata Corporation which was added as a new eligible employer. As a result of the acquisition, $27.1 million of assets were rolled into the Plan and were included in rollover contributions in the accompanying Statement of Changes in Net Assets.

The Committee is the Plan Administrator. The Committee consists of at least one officer of the Company and other individuals appointed by the Chief Executive Officer of the Company who are employed by the Company or a subsidiary of the Company. The recordkeeper of the Plan is Principal Financial Group (the Recordkeeper). The trustee of the Plan is Principal Trust Company (the Trustee).

**Eligibility**

Generally, eligible employees may participate in the Plan upon hire if they are at least 18 years of age and actively employed by the Employer. Leased employees, independent contractors, employees covered by a collectively bargained unit that has not bargained for the Plan, and employees eligible to participate in a multiemployer plan to which the Company contributes are generally not eligible to participate in the Plan.

**Deferral Contributions**

The Plan allows a participant to contribute, by payroll deduction, any whole percentage not to exceed 75 percent of the participant's eligible compensation for each pay period up to a maximum pre-tax and/or Roth deferral contribution of $23,500 for the 2025 Plan year. The Plan provides an automatic 6 percent deferral election feature and an automatic deferral escalation feature, which increases the participant's deferral percentage by one percent annually until the participant's deferral percentage reaches 15 percent, unless the participant opts out. Additionally, the Plan allows a participant who is eligible to make deferral contributions and will have attained age 50 before the close of the Plan year to make elective catch-up deferrals. The maximum catch-up deferral for 2025 was $7,500.

**Employer Matching Contributions**

Each Employer provides matching contributions on behalf of its participants equal to 50 percent of such participant's pre-tax and Roth deferral contributions up to 6 percent of the participant's annual eligible compensation as provided under the Plan or according to such other matching contribution formula as adopted by the Employer and approved by the Committee. All matching contributions are made in cash to the participant's matching contribution account and invested as directed by the participant.

**Profit Sharing/Retirement Contributions**

The Employer, in its sole discretion and subject to the Committee's approval, may make either profit sharing or retirement contributions, or both to the Plan on behalf of participants employed by that Employer. Participants may choose to invest profit sharing/retirement contributions allocated to their individual accounts in any or all of the available investment options. Profit sharing/retirement contributions totaling $13.6 million were credited to participant accounts for the year ended December 31, 2025.

------

**Rollover Contributions**

The Plan accepts rollover contributions from eligible retirement plans, including after-tax employee contributions and designated Roth accounts.

**Participant Accounts**

The Employers remit all authorized contributions made by the participants to the Trustee to be held in trust and invested for the respective accounts of the participants, pursuant to the terms of a trust agreement effective May 1, 2023. Individual accounts are maintained for each participant of the Plan. Each participant's account is credited with pre-tax deferral contributions, Roth deferral contributions, employer matching contributions, profit sharing/retirement contributions, and rollover contributions, as applicable, and allocated investment earnings and losses.

**Investment Options**

An election is made by each participant to allocate contributions in one percent increments to any or all of the 28 investment options available as of December 31, 2025. If a participant does not specify how contributions to their account are to be invested, they will automatically be invested in the applicable age appropriate target fund, as determined by the Committee. Contributions for Knife River common stock are used by the Trustee to purchase shares of Knife River Corporation common stock directly on the open market.

**Vesting**

A participant's interest in their pre-tax and Roth deferral accounts, matching contribution account, rollover account and ESOP account is at all times fully vested and nonforfeitable. Generally, a participant's interest in a profit sharing/retirement contribution account is 100 percent vested after completing three years of service. Knife River did not adopt a dividend policy during 2025 for the participants' ESOP accounts. If Knife River were to adopt a dividend policy, participants would be 100 percent vested in any dividends paid on Knife River common stock regardless of years of service.

**Distributions and Withdrawals**

The amount credited to participant accounts shall become payable to the participant or the participant's beneficiary/beneficiaries, as applicable, upon death, retirement, disability or other termination of employment with the Employers. The distribution of such amounts will be in accordance with the Plan, based on the method of payment elected by the participant or designated beneficiary/beneficiaries. If the participant's vested balance is $7,000 or less, the plan may distribute the balance in a lump sum, in accordance with the applicable requirements of the Internal Revenue Code (the Code). Generally, the Plan allows for a single-sum distribution or flexible installments over a period of time, not to exceed nine years; however, certain grandfathered distribution features are maintained for certain accounts affected by prior plan mergers.

Distributions with respect to investment options other than Knife River common stock are in the form of cash. Distributions with respect to Knife River common stock may be in the form of cash or in the form of Knife River common stock.

A participant may make in-service withdrawals (hardship or age 59 1/2) under certain conditions. Distributions from a participant's rollover account may be elected at any time.

**Notes Receivable from Participants**

A participant may be eligible to obtain a loan from the Plan. The minimum amount a participant can borrow is $1,000 and the maximum amount available for a loan is the lesser of $50,000 or one-half of the participant's vested account balance, subject to certain limitations. For each Participant, no more than two loans may be approved and no more than two loans may be outstanding at any time during the plan year. The loans are secured by the balance in the participant's account and shall bear a reasonable rate of interest equal to the Wall Street Journal Prime Rate plus 1% or such other commercially reasonable interest rate as determined by the Committee. Loans must be repaid over specified periods generally through payroll deduction and bear interest at a commercially reasonable rate in effect at the time the loan is made, as established by the Committee.

**Forfeited Accounts**

Forfeited non-vested accounts are used for any of the following: (i) to reinstate reemployed participants' forfeited accounts, (ii) to reduce employer contributions to the Plan and (iii) to reduce administrative expenses incurred by the Plan. As of December 31, 2025 and 2024, forfeited non-vested accounts totaled $66,000 and $50,000, respectively. These accounts will be used to reduce future employer contributions. For the year ended December 31, 2025, employer contributions were reduced by $1.1 million from forfeited non-vested accounts.

------

**<u>Note 2 - Summary of Significant Accounting Policies</u>**

**Basis of Accounting**

The financial statements of the Plan are maintained on an accrual basis.

**Use of Estimates**

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and changes therein, and disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

**Investment Valuation and Income Recognition**

Investments held by the Plan are carried at fair value. The Plan's common stock and mutual fund investment valuations, as determined by the Trustee, are based on published market quotations.

The fully benefit-responsive investment contract, the New York Life Insurance Anchor Account, is stated at contract value.

At December 31, 2025 and 2024, there were 15 collective trust funds, which are valued at the fair value reported by the fund manager based on the underlying investments within each fund and are expressed in units representing the net asset value of each fund.

Securities transactions are recorded on a trade date basis. Dividend income is recorded upon receipt and Interest income is recorded as earned.

For more information on fair value measurements, see Note 4.

**Notes Receivable from Participants**

Notes receivable from participants are measured at their unpaid principal balance plus any accrued interest. Delinquent notes receivable from participants are recorded as distributions based on the terms of the Plan document.

**Benefit Payments**

Distributions to Plan participants are recorded when paid.

**Contributions**

Employer and participant contributions are recorded by the Plan when received or determined to be receivable. Participant contributions are deposited with the Plan by the Employers through payroll reductions.

**Administrative Expenses and Revenue Sharing**

Administrative expenses of the Plan related to Trustee, recordkeeping, legal and audit fees are paid primarily by the Plan, which are then allocated to the participants based on their account balances. Administrative expenses are also paid by participants through the Plan including Knife River common stock commissions, loan fees and terminated participant account fees. The total paid for these expenses was $990,000 for the year ended December 31, 2025.

Fees or commissions associated with each of the investment options other than Knife River common stock are paid primarily by participants as a deduction from the amount invested or an offset to investment earnings, which are offset in part by revenue sharing agreements with certain providers. For the year ended December 31, 2025, fees and commissions paid were approximately $2.9 million and revenue sharing earned was approximately $125,000.

**Risks and Uncertainties**

Investments, in general, are subject to various risks, including credit, interest rate and overall market volatility risks. Due to the level of risk associated with certain investment securities, it is likely that changes in values of investment securities will occur in the near term and that such changes could materially affect participants' account balances and the amounts reported in the statements of net assets available for benefits.

------

**Concentration of Investments**

The following presents investments that represent 10 percent or more of the Plan's net assets available as of December 31:

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **2025** | **2025** | 2024 | 2024 |
| | **Amount** | **Percent of net assets** | Amount | Percent of net assets |
| Fidelity 500 Index Fund | $**99376462** | **10%** | \*\* | \*\* |
| Knife River Common Stock\* | **\*\*** | **\*\*** | 89044385 | 11% |
| Vanguard Institutional Index Fund | **\*\*** | **\*\*** | 84442591 | 10% |
| &nbsp;&nbsp;\* Indicates a party-in-interest investment. | &nbsp;&nbsp;\* Indicates a party-in-interest investment. | &nbsp;&nbsp;\* Indicates a party-in-interest investment. | &nbsp;&nbsp;\* Indicates a party-in-interest investment. | &nbsp;&nbsp;\* Indicates a party-in-interest investment. |
| \*\* Investment did not represent 10 percent or more of the Plan's net assets available for benefits. | \*\* Investment did not represent 10 percent or more of the Plan's net assets available for benefits. | \*\* Investment did not represent 10 percent or more of the Plan's net assets available for benefits. | \*\* Investment did not represent 10 percent or more of the Plan's net assets available for benefits. | \*\* Investment did not represent 10 percent or more of the Plan's net assets available for benefits. |

---

**Subsequent Events**

The Plan has evaluated the impact of events occurring after December 31, 2025, up to the date of issuance of these financial statements on June 17, 2026, that would require recognition or disclosure in the financial statements. There were no subsequent events that would require recognition or disclosure in the financial statements.

**<u>Note 3 - Investment Contract with Insurance Company</u>**

The Plan has a fully benefit-responsive investment contract with New York Life Insurance Company (NYL Insurance). NYL Insurance maintains the contributions in a pooled separate account, which is credited with earnings on the underlying investments and charged for participant withdrawals and administrative expenses. The investment contract is maintained to provide a stable investment option and minimize risk to participants, and the issuer is contractually obligated to repay the principal, along with a variable interest rate that is guaranteed to the Plan.

Because the guaranteed investment contract is fully benefit-responsive, contract value is the relevant measurement attributable for that portion of the net assets available for benefits attributable to the guaranteed investment contract. The guaranteed investment contract is presented at contract value on the face of the statement of net assets available for benefits. Contract value represents contributions made under the contract, plus interest and dividends credited, less participant withdrawals and administrative expenses. As of December 31, 2025 and 2024, the contract value of the traditional fully benefit-responsive contract with NYL Insurance was $55.9 million and $61.7 million, respectively. Participants may ordinarily direct the withdrawal or transfer of all or a portion of their investment at contract value. The contract has certain restrictions that impact the ability to collect the full contract value. For example, withdrawals due to events initiated by the Company including, but not limited to, total or partial termination of the Plan, group lay-offs or early retirement incentives, may result in a penalty if these withdrawals exceed limitations defined in the contract. The Company believes that the occurrence of events that would cause the plan to transact at less than contract value is not probable. NYL Insurance may not terminate the contract at any amount less than contract value.

NYL Insurance is contractually obligated to pay the principal and any interest and dividends that have been credited to the Plan. The crediting interest rate is based on a formula agreed upon with the issuer, but may not be less than zero percent. Such interest rates are reviewed not less frequently than quarterly nor more frequently than daily for resetting.

**<u>Note 4 - Fair Value Measurements</u>**

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The Financial Accounting Standards Board Accounting Standards Codification (ASC) establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs. The asset's or liability's fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs. There are three levels of inputs that may be used to measure fair value:

Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date;

Level 2 - inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly; or

Level 3 - unobservable inputs for the asset or liability.

The estimated fair values of the Plan's assets measured on a recurring basis are determined using the market approach and are corroborated using third-party market data.

Common stock: Valued at the closing price reported on the active market on which the individual securities are traded.

Mutual funds: Valued at the net asset value of shares held by the Plan based on published market quotations on active markets.

------

Collective trust funds: Investments in the collective trust funds are valued at net asset value (NAV), as provided by the trustee, which is used as a practical expedient to estimate fair value. The NAV is based on the fair value reported by the fund managers based on the underlying investments within each fund less its liabilities. Investments measured at NAV do not have publicly quoted prices. This practical expedient is not used when it is determined to be probable that the fund will sell the investment for an amount different than the NAV. Participant transactions may occur daily. The fair value of the underlying investments held by the common collective trusts is generally based on quoted prices in active markets.

The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the valuation methods are considered appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date.

The Plan's assets measured at fair value were as follows:

---

| | | | | |
|:---|:---|:---|:---|:---|
| | Fair Value Measurements | Fair Value Measurements | Fair Value Measurements | |
| | at December 31, 2025, Using | at December 31, 2025, Using | at December 31, 2025, Using | |
| | Quoted Prices in Active Markets for Identical Assets <br>(Level 1) | Significant Other Observable Inputs <br>(Level 2) | Significant Unobservable Inputs <br>(Level 3) |<br>Balance at December 31, 2025 |
| Assets: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;Mutual funds | $404366455 | $— | $— | $404366455 |
| &nbsp;&nbsp;&nbsp;Common stock | 62037055 |  |  | 62037055 |
| &nbsp;&nbsp;&nbsp;Total assets in the fair value hierarchy | 466403510 |  |  | 466403510 |
| Collective trust fund investments measured at net asset value (a) |  |  |  | 405940105 |
| &nbsp;&nbsp;&nbsp;Total assets measured at fair value | $466403510 | $— | $— | $872343615 |
| (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. |

---

---

| | | | | |
|:---|:---|:---|:---|:---|
| | Fair Value Measurements | Fair Value Measurements | Fair Value Measurements | |
| | at December 31, 2024, Using | at December 31, 2024, Using | at December 31, 2024, Using | |
| | Quoted Prices in Active Markets for Identical Assets <br>(Level 1) | Significant Other Observable Inputs <br>(Level 2) | Significant Unobservable Inputs <br>(Level 3) |<br>Balance at December 31, 2024 |
| Assets: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;Mutual funds | $346467182 | $— | $— | $346467182 |
| &nbsp;&nbsp;&nbsp;Common stock | 89044385 |  |  | 89044385 |
| &nbsp;&nbsp;&nbsp;Total assets in the fair value hierarchy | 435511567 |  |  | 435511567 |
| Collective trust fund investments measured at net asset value (a) |  |  |  | 317222877 |
| &nbsp;&nbsp;&nbsp;Total assets measured at fair value | $435511567 | $— | $— | $752734444 |
| (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. | (a) In accordance with ASC 820 - *Fair Value*, certain investments that were measured at net asset value per share (or its equivalent) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the line items presented in the Statements of Net Assets Available for Benefits. |

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The Plan has investments in which the fair value is measured using the NAV per share as a practical expedient. At December 31, 2025, there were no unfunded commitments or redemption restrictions on these investments.

**<u>Note 5 - Federal Income Taxes</u>**

The Internal Revenue Service (IRS) has determined and informed the Company by a letter dated November 13, 2024, that the Plan and related trust are designed for qualification as exempt from federal income taxes in accordance with applicable sections

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of the Code. The Company believes that the Plan is designed and is being operated in compliance with the applicable requirements of the Code.

GAAP requires Plan management to evaluate tax positions taken by the Plan. The effects of an uncertain tax position are recognized in the financial statements when the position is more likely than not, based on the technical merits, to be sustained upon examination by the IRS. The Plan administrator has analyzed the tax positions taken by the Plan and has concluded that as of December 31, 2025 and 2024, there are no uncertain positions taken or expected to be taken and no interest or penalties related to uncertain tax positions. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress.

**<u>Note 6 - Related-Party and Party-In-Interest Transactions</u>**

At December 31, 2025 and 2024, the Plan held 881,834 and 876,076 shares, respectively, of common stock of Knife River, the plan sponsor. The market value of Knife River common stock totaled approximately $62.0 million and $89.0 million at December 31, 2025 and 2024, respectively. Shares of the plan sponsor were bought and sold in the open market at quoted fair market values at the date of purchase and sale. These shares qualify as exempt party-in-interest transactions and are allowable under ERISA.

The Trustee of the Plan manages certain plan investments. Therefore, these transactions qualify as party-in-interest transactions and are denoted as such on the supplemental schedule of assets (held at end of year). However, they are exempt from the prohibited transaction rules under ERISA.

The Plan allows participants to borrow from their fund accounts and, therefore, these transactions qualify as party-in-interest.

**<u>Note 7 - Reconciliation of the Financial Statements to the Form 5500</u>**

The following is a reconciliation of net assets available for benefits per the financial statements to the Form 5500:

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| | | |
|:---|:---|:---|
| December 31, | **2025** | 2024 |
| Net assets available for benefits per the financial statements | $**964481634** | $856580528 |
| Deemed distributions | **(143785)** | (151505) |
| Defaulted loans | **(114721)** | (41608) |
| Net assets available for benefits per the Form 5500 | $**964223128** | $856387415 |

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The following is a reconciliation of the changes in net assets available for benefits per the financial statements to the Form 5500 for the period ended December 31, 2025:

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| | |
|:---|:---|
| Net increase in net assets available for benefits per the financial statements | $**107901106** |
| Change in deemed distributions | **7720** |
| Change in defaulted loans | **(73113)** |
| Total net income per the Form 5500 | $**107835713** |

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**SUPPLEMENTAL** 

**SCHEDULES**

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**Knife River Corporation**

**401(k) Retirement Plan**

**Employer Identification Number (92-1008893) - Plan Number (001)**

**Schedule H, Line 4i - Schedule of Assets (Held at End of Year)**

**December 31, 2025**

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| | | | | |
|:---|:---|:---|:---|:---|
| (a) | (b) Identity of issue, borrower, lessor, or similar party | (c) Description of investments (number of shares) | (d) Cost | (e) Current value |
| \* | Knife River Common Stock | 881834 | \*\* | $62037055 |
|  | Mutual Funds: |  |  |  |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;American Funds - EuroPacific Growth Fund | 318974 | \*\* | 19323454 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;BlackRock Inflation Protected Bond Fund | 487395 | \*\* | 4781347 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;DFA International Value Portfolio Fund | 661098 | \*\* | 18900806 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Dodge & Cox Balanced Fund | 4190810 | \*\* | 56575932 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Fidelity Extended Market Index Fund | 349756 | \*\* | 35209911 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Fidelity 500 Index Fund | 418040 | \*\* | 99376462 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Fidelity Total International Index Fund | 545530 | \*\* | 9448588 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Fidelity US Bond Index Fund | 2700443 | \*\* | 28516679 |
| \* | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Principal Diversified Real Asset Fund | 59611 | \*\* | 729048 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Institutional Large Cap Growth Fund | 1031970 | \*\* | 87686499 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price U.S. Equity Research Fund | 650308 | \*\* | 43817729 |
|  | Collective Trust Funds: |  |  |  |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GW&K Small/Mid Cap Core I Fund | 739753 | \*\* | 20262898 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2010 Fund | 103980 | \*\* | 2598456 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2015 Fund | 168995 | \*\* | 4633832 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2020 Fund | 583170 | \*\* | 17454288 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2025 Fund | 1228419 | \*\* | 40353553 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2030 Fund | 1501679 | \*\* | 54465914 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2035 Fund | 1178935 | \*\* | 46909827 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2040 Fund | 1195084 | \*\* | 51030074 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2045 Fund | 1397004 | \*\* | 62096821 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2050 Fund | 727313 | \*\* | 32554544 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2055 Fund | 808248 | \*\* | 36217601 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2060 Fund | 739007 | \*\* | 21187331 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement 2065 Fund | 351367 | \*\* | 6300018 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T. Rowe Price Retirement Balanced Fund | 107970 | \*\* | 2454148 |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Loomis Sayles Core Plus Fixed Income Fund | 424531 | \*\* | 7420800 |
|  | Fully Benefit-Responsive Investment Contract: |  |  |  |
|  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;New York Life Insurance Anchor Account | 55863527 | \*\* | 55863527 |
|  | Total Investments |  |  | 928207142 |
| \* | Participant Loan Funds \*\*\* | 4.25% to 10.00% | $— | 24464916 |
|  |  |  |  | $952672058 |

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\*&nbsp;&nbsp;&nbsp;&nbsp;Indicates party-in-interest investment.

\*\*&nbsp;&nbsp;&nbsp;&nbsp;Cost information is not required for participant-directed investments, therefore it is not included.

\*\*\*&nbsp;&nbsp;&nbsp;&nbsp;Loan maturities range from January 3, 2026 through November 1, 2040.

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**<u>Exhibit Index</u>**

The following document is filed as part of this report:

Exhibit Number Exhibit Description <br> 23 [Consent of Independent Registered Public Accounting Firm](a2025form11-kex23.htm)

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**<u>Signature</u>**

Pursuant to the requirements of the Securities Exchange Act of 1934, the Employee Benefits Committee of the Knife River Corporation 401(k) Retirement Plan has duly caused this annual report to be signed on its behalf by the undersigned hereunto duly authorized.

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| | | | |
|:---|:---|:---|:---|
| | | Knife River Corporation | Knife River Corporation |
| | | 401(k) Retirement Plan | 401(k) Retirement Plan |
| DATE: | June 17, 2026 | BY: | /s/ Nathan W. Ring |
| | | | Nathan W. Ring |
| | | | Chairman, Employee Benefits Committee |

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## Ex-23

**Consent of Independent Registered Public Accounting Firm**

We have issued our report dated June 17, 2026, with respect to the financial statements and supplemental information included in the Annual Report of Knife River Corporation 401(k) Retirement Plan on Form 11-K for the year ended December 31, 2025. We consent to the incorporation by reference of said report in the Registration Statement of Knife River Corporation on Form S-8 (File No. 333-272356).

/s/ GRANT THORNTON LLP

Chicago, Illinois

June 17, 2026

<br>