SOUTHERN MISSOURI BANCORP, INC., 11-K filed on 12/10/2025
Annual Report of Employee Stock Plans
v3.25.3
Document and Entity Information
12 Months Ended
Jun. 30, 2025
Document Information [Line Items]  
Document Type 11-K
Entity Registrant Name Southern Missouri Bancorp, Inc.
Entity Central Index Key 0000916907
Amendment Flag false
Southern Bank 401(k) Retirement Plan (the Plan)  
Document Information [Line Items]  
Document Type 11-K
Amendment Flag false
v3.25.3
STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS - Southern Bank 401(k) Retirement Plan (the Plan) - USD ($)
Jun. 30, 2025
Jun. 30, 2024
EBP, Statement of Net Asset Available for Benefit [Line Items]    
Investments, At Fair Value $ 69,533,358 $ 56,940,813
Receivables    
Notes receivable from participants 876,590 637,773
Employer's contributions 1,748,566 1,269,919
Total Receivables 2,625,156 1,907,692
Net Assets Available for Benefits $ 72,158,514 $ 58,848,505
v3.25.3
STATEMENTS OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS - Southern Bank 401(k) Retirement Plan (the Plan)
12 Months Ended
Jun. 30, 2025
USD ($)
Investment Income  
Net appreciation in fair value of investments $ 7,742,646
Interest and dividends 2,669,422
Net investment income 10,412,068
Interest Income on Notes Receivable from Participants 50,855
Contributions  
Participants 2,059,710
Employer 2,932,509
Rollovers 376,156
Total contributions 5,368,375
Total additions 15,831,298
Deductions  
Benefits paid to participants 2,511,613
Administrative fees 9,676
Total deductions 2,521,289
Net Increase 13,310,009
Net Assets Available for Benefits, Beginning of Year 58,848,505
Net Assets Available for Benefits, End of Year $ 72,158,514
v3.25.3
Description of the Plan
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Description of Plan [Line Items]  
Description of the Plan

Note 1:Description of the Plan

The following description of Southern Bank 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

The Plan is a defined contribution plan sponsored by Southern Bank (the Bank), a wholly-owned subsidiary of Southern Missouri Bancorp, Inc. (the Company), for the benefit of its employees who have at least one year of service and are age 21 or older. The Plan is subject to the provisions of the Employee Retirement Income Security Act of 1974 (ERISA).

The Bank previously also maintained a qualified Employee Stock Ownership Plan (ESOP). The Bank merged the ESOP into the Plan effective October 1, 2010. Participant accounts under the ESOP are maintained as a separate source (ESOP Source) under the Plan with ESOP provisions concerning matters such as vesting, withdrawals, loans, dividends, and distributions remaining in effect.

The Plan is administered by the Bank. Capital Bank and Trust Company is the trustee of the Plan. American Funds serves as the Plan custodian.

Contributions

The Plan permits eligible employees to make voluntary contributions to the Plan up to the annual limit set by the Internal Revenue Service (IRS). Employee rollover contributions are also permitted. Participants who have attained age 50 before the end of the calendar year are eligible to make catch-up contributions.

The Bank makes safe harbor matching contributions of 100% of employees’ salary deferral amounts on the first 3% of employees’ compensation, and 50% of employees’ salary deferral amounts on the next 2% of employees’ compensation. The Bank also makes profit-sharing contributions. Bank profit-sharing contributions are discretionary as determined by the Bank’s Board of Directors. Contributions are subject to certain limitations. Forfeitures are used to reduce Bank contributions.

Participant Investment Account Options

Investment account options available include various funds and common stock of the Company. Each participant has the option of directing his contributions into any of the separate investment accounts and may change the allocation daily.

Participant Accounts

Each participant’s account is credited with the participant’s contribution, the Bank’s contribution, and plan earnings, and is charged with an allocation of administrative expenses. Allocations are based on participant earnings or account balances, as defined. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s vested account.

Vesting

Participants are immediately vested in their voluntary contributions plus earnings thereon. Bank matching contributions and ESOP source contributions are vested at a rate of 20% per year of service beginning with completion of the second year of service. A participant becomes fully vested with completion of their sixth year of service. The non-vested balance is forfeited upon termination of service. Forfeitures are used to reduce Bank contributions.

Payment of Benefits

Under the terms of the Plan, participants are entitled to receive the amount credited to their accounts upon normal retirement at the age of 65 or disability retirement. Participants terminating employment prior to retirement are entitled to receive that portion of their account that is vested. In the event of death, the participant’s account becomes fully vested and is paid to the designated beneficiary. Distributions under the Plan are payable in a lump sum or through installments. Payments through installments are only available to Participants with a vested account balance in excess of $5,000 who terminate at normal retirement age or later. At June 30, 2025 and 2024, Plan assets included no amounts allocated to accounts of terminated or retired participants who have elected to withdraw from the Plan but which had not yet been paid.

Forfeited Accounts

At June 30, 2025 and 2024, forfeited non-vested accounts totaled $62,488 and $38,567, respectively. These accounts will be used to reduce future Bank contributions. Also, in 2025, employer contributions were reduced by $45,391 from forfeited non-vested accounts.

Notes Receivable from Participants

The Plan Document includes provisions authorizing loans from the Plan to active eligible participants. The minimum amount of a loan shall be $1,000. The maximum amount of a participant’s loans is determined by the available loan balance restricted to the lesser of $50,000 or 50% of the participant’s vested account balance. All loans are covered by demand notes and are repayable over a period not to exceed five years. Loans are repaid through payroll withholdings unless the participant is paying the loan in full. Interest on the loans is fixed for the term of the loan at a rate one percentage point above the Wall Street Journal’s published prime rate of interest on the first day of the month in which the loan was made.

Plan Termination

Although it has not expressed an intention to do so, the Bank has the right under the Plan to discontinue its contributions at any time and to terminate the Plan, subject to the provisions of ERISA. In the event of plan termination, participants will become 100% vested in their accounts.

v3.25.3
Summary of Significant Accounting Policies
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Accounting Policy [Line Items]  
Summary of Significant Accounting Policies

Note 2:Summary of Significant Accounting Policies

Basis of Accounting

The accompanying financial statements are prepared on the accrual basis of accounting.

Use of Estimates

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

Investment Valuation and Income Recognition

Quoted market prices, if available, are used to value investments. Common stock is valued at the closing price reported on the active market on which the individual security is traded. Mutual funds and the money market fund are valued at the net asset value (NAV) of shares held by the plan at year end.

Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded on the accrual basis. Dividends are recorded on the ex-dividend date. Net appreciation includes the Plan’s gains and losses on investments bought and sold as well as held during the year.

Notes Receivable from Participants

Notes receivable from participants are measured at their unpaid principal balance plus any accrued but unpaid interest. Delinquent participant loans are reclassified as distributions based upon the terms of the plan document.

Plan Tax Status

The Plan operates under a non-standardized adoption agreement in connection with a pre-approved defined contribution plan document sponsored by Capital Group Retirement Plan Services. This pre-approved plan document has been filed with the appropriate agency. The Plan has not obtained or requested a determination letter. However, the Plan Administrator believes that the Plan is

currently designed and being operated in compliance with the applicable requirements of the Internal Revenue Code and that the Plan was qualified, and the related trust was tax exempt.

Accounting principles generally accepted in the United States of America require Plan management to evaluate tax positions taken by the Plan and recognize a tax liability if the Plan has taken an uncertain position that more likely than not would not be sustained upon examination by the IRS. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress.

Payment of Benefits

Benefit payments to participants are recorded upon distribution.

Administrative Expenses

Administrative expenses may be paid by the Bank or the Plan, at the Bank’s discretion.

Contributions

Contributions from Plan participants and the safe harbor matching contributions from the Employer are recorded in the year in which the employee contributions are withheld from compensation.

v3.25.3
Related-Party and Party-in-Interest Transactions
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Related Party and Party-in-Interest Transactions [Line Items]  
Related-Party and Party-in-Interest Transactions

Note 3: Related-Party and Party-in-Interest Transactions

Party-in-interest transactions include those with fiduciaries or employees of the Plan, any person who provides services to the Plan, an employer whose employees are covered by the Plan, a person who owns 50 percent or more of such an employer, or relatives of such persons.

The Plan allows participants to invest their account balances in shares of the Company. The number of shares of common stock held by the Plan at June 30, 2025 and 2024 was 417,574 shares and 411,674 shares, respectively, and the Plan received dividends of $377,932 during the year ended June 30, 2025.

The plan incurs expenses related to general administrative and record keeping. The Company pays certain administrative expenses and accounting and auditing fees relating to the Plan and provides certain administrative services at no cost to the plan.

v3.25.3
Disclosures About Fair Value of Plan Assets
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Investment, Fair Value and NAV [Line Items]  
Disclosures About Fair Value of Plan Assets

Note 4:Disclosures About Fair Value of Plan Assets

Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements must maximize the use of observable inputs and minimize the use of unobservable inputs. There is a hierarchy of three levels of inputs that may be used to measure fair value:

Level 1

Quoted prices in active markets for identical assets

Level 2

Observable inputs other than Level 1 prices, such as quoted prices for similar assets; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets

Level 3

Unobservable inputs that are supported by little or no market activity and significant to the fair value of the assets

Recurring Measurements

The following tables present the fair value measurements of assets recognized in the accompanying statements of net assets available for benefits measured at fair value on a recurring basis and the level within the fair value hierarchy in which the fair value measurements fall at June 30, 2025 and 2024:

June 30, 2025

    

Fair Value Measurements Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable Inputs

Fair Value

(Level 1)

(Level 2)

(Level 3)

Company security

$

22,874,722

$

22,874,722

$

$

Mutual funds

44,494,883

44,494,883

Money market fund

2,163,753

2,163,753

$

69,533,358

$

69,533,358

$

$

June 30, 2024

    

Fair Value Measurements Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable Inputs

Fair Value

(Level 1)

(Level 2)

(Level 3)

Company security

$

18,529,431

$

18,529,431

$

$

Mutual funds

36,923,067

36,923,067

Money market fund

1,488,315

1,488,315

$

56,940,813

$

56,940,813

$

$

Following is a description of the valuation methodologies and inputs used for assets measured at fair value on a recurring basis and recognized in the accompanying statements of net assets available for benefits, as well as the general classification of such assets pursuant to the valuation hierarchy. There have been no significant changes in the valuation techniques during the year ended June 30, 2025. In addition, the Plan had no assets measured at fair value on a nonrecurring basis.

Investments

Where quoted market prices are available in an active market, securities are classified within Level 1 of the valuation hierarchy.

v3.25.3
Reconciliation of Financial Statements to Form 5500
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Reconciliation of Financial Statement to Form 5500 [Line Items]  
Reconciliation of Financial Statements to Form 5500

Note 5:Reconciliation of Financial Statements to Form 5500

The following is a reconciliation of net assets available for benefits per the financial statements at June 30, 2025 and 2024, to Form 5500:

2025

2024

Net assets available for benefits per the financial statements

$

72,158,514

$

58,848,505

Less: Employer's contributions receivable

1,748,566

1,269,919

Net assets available for benefits per Form 5500

$

70,409,948

$

57,578,586

The following is a reconciliation of contributions per the financial statements for the year ended June 30, 2025, to Form 5500:

2025

 

Contributions per the financial statements

$

5,368,375

Add: Employer's contributions receivable at June 30, 2024

1,269,919

Less: Employer's contributions receivable at June 30, 2025

(1,748,566)

Contributions per Form 5500

$

4,889,728

v3.25.3
Risks and Uncertainties
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Risk and Uncertainty [Line Items]  
Risks and Uncertainties

Note 6:Risks and Uncertainties

The Plan invests in various investment securities. Investment securities are exposed to various risks such as interest rate, market and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect the participants’ account balances, and the amounts reported in the statements of net assets available for benefits.

v3.25.3
Subsequent Events
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Subsequent Event [Line Items]  
Subsequent Events

Note 7:Subsequent Events

Effective September 16, 2025, the Plan was amended and restated with Fidelity Management Trust Company (Fidelity) appointed as the new trustee of the Plan. Plan assets transferred to Fidelity were from funds comparable to those offered by Capital Bank and Trust Company. The conversion initiated a “Black Out” period beginning September 8, 2025, and continued through October 14, 2025. During this period, funds could not be withdrawn from the Plan until Fidelity had time to accurately complete the conversion. During this period, employee contributions continued to be made through payroll deductions, and the contributions were transferred to Fidelity and invested in funds as requested by each participant.

Concurrent with the transition to Fidelity, the Plan was amended, and the following provisions were changed. The eligibility requirement was lowered from one year of employment and 1,000 hours of service to two months of employment with no minimum hours of service. This change is for all contribution sources except profit-sharing. New hires after August 1, 2025, will be automatically enrolled in the Plan at a deferral rate of 3%. Deferral rates and investment choices can be adjusted at any time. Participant loans for the purchase of a principal residence can now be repayable over a period not to exceed 10 years.

v3.25.3
Summary of Significant Accounting Policies (Policies) - Southern Bank 401(k) Retirement Plan (the Plan)
12 Months Ended
Jun. 30, 2025
EBP, Accounting Policy [Line Items]  
Basis of Accounting

Basis of Accounting

The accompanying financial statements are prepared on the accrual basis of accounting.

Use of Estimates

Use of Estimates

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

Investment Valuation and Income Recognition

Investment Valuation and Income Recognition

Quoted market prices, if available, are used to value investments. Common stock is valued at the closing price reported on the active market on which the individual security is traded. Mutual funds and the money market fund are valued at the net asset value (NAV) of shares held by the plan at year end.

Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded on the accrual basis. Dividends are recorded on the ex-dividend date. Net appreciation includes the Plan’s gains and losses on investments bought and sold as well as held during the year.

Notes Receivable from Participants

Notes Receivable from Participants

Notes receivable from participants are measured at their unpaid principal balance plus any accrued but unpaid interest. Delinquent participant loans are reclassified as distributions based upon the terms of the plan document.

Plan Tax Status

Plan Tax Status

The Plan operates under a non-standardized adoption agreement in connection with a pre-approved defined contribution plan document sponsored by Capital Group Retirement Plan Services. This pre-approved plan document has been filed with the appropriate agency. The Plan has not obtained or requested a determination letter. However, the Plan Administrator believes that the Plan is

currently designed and being operated in compliance with the applicable requirements of the Internal Revenue Code and that the Plan was qualified, and the related trust was tax exempt.

Accounting principles generally accepted in the United States of America require Plan management to evaluate tax positions taken by the Plan and recognize a tax liability if the Plan has taken an uncertain position that more likely than not would not be sustained upon examination by the IRS. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress.

Payment of Benefits

Payment of Benefits

Benefit payments to participants are recorded upon distribution.

Administrative Expenses

Administrative Expenses

Administrative expenses may be paid by the Bank or the Plan, at the Bank’s discretion.

Contributions

Contributions

Contributions from Plan participants and the safe harbor matching contributions from the Employer are recorded in the year in which the employee contributions are withheld from compensation.

v3.25.3
Disclosures About Fair Value of Plan Assets (Tables)
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Investment, Fair Value and NAV [Line Items]  
Recurring Measurements

June 30, 2025

    

Fair Value Measurements Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable Inputs

Fair Value

(Level 1)

(Level 2)

(Level 3)

Company security

$

22,874,722

$

22,874,722

$

$

Mutual funds

44,494,883

44,494,883

Money market fund

2,163,753

2,163,753

$

69,533,358

$

69,533,358

$

$

June 30, 2024

    

Fair Value Measurements Using

Quoted Prices in
Active Markets for
Identical Assets

Significant Other
Observable Inputs

Significant
Unobservable Inputs

Fair Value

(Level 1)

(Level 2)

(Level 3)

Company security

$

18,529,431

$

18,529,431

$

$

Mutual funds

36,923,067

36,923,067

Money market fund

1,488,315

1,488,315

$

56,940,813

$

56,940,813

$

$

v3.25.3
Reconciliation of Financial Statements to Form 5500 (Tables)
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Reconciliation of Financial Statement to Form 5500 [Line Items]  
Reconciliation of net assets available for benefits per the financial statements

2025

2024

Net assets available for benefits per the financial statements

$

72,158,514

$

58,848,505

Less: Employer's contributions receivable

1,748,566

1,269,919

Net assets available for benefits per Form 5500

$

70,409,948

$

57,578,586

2025

 

Contributions per the financial statements

$

5,368,375

Add: Employer's contributions receivable at June 30, 2024

1,269,919

Less: Employer's contributions receivable at June 30, 2025

(1,748,566)

Contributions per Form 5500

$

4,889,728

v3.25.3
Schedule H Line 4i - Schedule of Assets (Tables)
12 Months Ended
Jun. 30, 2025
Southern Bank 401(k) Retirement Plan (the Plan)  
EBP, Schedule of Asset Held for Investment [Line Items]  
Schedule H, Line 4i - Schedule of Assets

Investment Type and Issuer

Description of Investment

Current Value

*

American Funds Money Market Fund

  

2,163,753

  

shares

  

$

2,163,753

Mutual Funds

*

American Funds Bond Fund of America R4

69,499

shares

789,511

*

American Funds Intermediate Bond Fund of America R4

40,401

shares

512,291

*

American Funds Income Fund of America R4

32,958

shares

875,683

Franklin Income Fund A

96,410

shares

232,349

*

American Funds American Balanced Fund R4

44,515

shares

1,629,692

Invesco Comstock A

14,200

shares

432,964

*

American Funds Fundamental Investors R4

23,456

shares

2,054,053

*

American Funds Investment Company of America R4

59,554

shares

3,733,460

Ishares S&P 500 Index A

1,045

shares

758,653

*

American Funds Growth Fund of America R4

56,926

shares

4,618,961

*

American Funds New Perspective Fund R4

25,060

shares

1,714,615

*

American Funds New World Fund R4

10,467

shares

924,172

Fidelity Advisor Growth Opportunities A

5,764

shares

1,113,100

Fidelity Advisor Financials A

3,365

shares

127,091

Fidelity Advisor Technology A

5,924

shares

757,126

Putnam Large Cap Growth A

14,058

shares

1,021,564

Putnam Small Cap Growth Fund A

19,396

shares

1,452,187

Victory Sycamore Established Value A

40,313

shares

1,828,609

Invesco Small Cap Value A

8,335

shares

196,288

*

American Funds 2010 Target Date Fund R4

18,615

shares

231,388

*

American Funds 2015 Target Date Fund R4

11,900

shares

156,126

*

American Funds 2020 Target Date Fund R4

48,846

shares

705,339

*

American Funds 2025 Target Date Fund R4

65,791

shares

1,070,427

*

American Funds 2030 Target Date Fund R4

159,536

shares

2,970,559

*

American Funds 2035 Target Date Fund R4

208,855

shares

4,304,496

*

American Funds 2040 Target Date Fund R4

138,574

shares

3,109,608

*

American Funds 2045 Target Date Fund R4

97,659

shares

2,265,697

*

American Funds 2050 Target Date Fund R4

92,975

shares

2,125,416

*

American Funds 2055 Target Date Fund R4

55,265

shares

1,591,089

*

American Funds 2060 Target Date Fund R4

39,483

shares

775,058

*

American Funds 2065 Target Date Fund R4

21,468

shares

412,398

*

American Funds 2070 Target Date Fund R4

409

shares

4,913

Subtotal - Mutual Funds

44,494,883

*

Southern Missouri Bancorp, Inc. Common Stock (SMBC)

417,574

shares

22,874,722

Various maturity dates through 2030

*

Notes Receivable from Participants

interest rates from 4.25% to 9.50%

876,590

$

70,409,948

* Party-in-interest

v3.25.3
Description of the Plan (Details) - Southern Bank 401(k) Retirement Plan (the Plan) - USD ($)
12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Vesting    
Vesting Percentage Per Year 20.00%  
Years of Service Before Vesting Begins 2 years  
Years to Full Vesting 6 years  
Payment of Benefits    
Minimum Account Balance Required for Installment Payments $ 5,000  
Asset allocated to accounts of terminated or retired participants 0 $ 0
Forfeited Accounts    
Forfeited non-vested accounts 62,488 $ 38,567
Employer contributions reduced amount from forfeited non-vested accounts $ 45,391  
First 3% of employees' compensation    
EBP, Description of Plan [Line Items]    
Matching contributions 100.00%  
Match percentage of employees' compensation 3.00%  
Next 2% of employees' compensation    
EBP, Description of Plan [Line Items]    
Matching contributions 50.00%  
Match percentage of employees' compensation 2.00%  
v3.25.3
Related-Party and Party-in-Interest Transactions (Details) - Southern Bank 401(k) Retirement Plan (the Plan) - USD ($)
12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
EBP, Related Party and Party-in-Interest Transactions [Line Items]    
Dividends received $ 377,932  
Common Stock [Member]    
EBP, Related Party and Party-in-Interest Transactions [Line Items]    
Number of shares of common stock held by the Plan 417,574 411,674
v3.25.3
Disclosures About Fair Value of Plan Assets (Details) - Southern Bank 401(k) Retirement Plan (the Plan) - USD ($)
Jun. 30, 2025
Jun. 30, 2024
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets $ 69,533,358 $ 56,940,813
Quoted Prices in Active Markets for Identical Assets (Level 1)    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 69,533,358 56,940,813
Company security    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 22,874,722 18,529,431
Company security | Quoted Prices in Active Markets for Identical Assets (Level 1)    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 22,874,722 18,529,431
Mutual funds    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 44,494,883 36,923,067
Mutual funds | Quoted Prices in Active Markets for Identical Assets (Level 1)    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 44,494,883 36,923,067
Money market fund    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets 2,163,753 1,488,315
Money market fund | Quoted Prices in Active Markets for Identical Assets (Level 1)    
EBP, Investment, Fair Value and NAV [Line Items]    
Fair value measurements of assets $ 2,163,753 $ 1,488,315
v3.25.3
Reconciliation of Financial Statements to Form 5500 (Details) - Southern Bank 401(k) Retirement Plan (the Plan) - USD ($)
12 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Reconciliation of net assets available for benefits    
Net assets available for benefits per the financial statements $ 72,158,514 $ 58,848,505
Less: Employer's contributions receivable 1,748,566 1,269,919
Net assets available for benefits per Form 5500 70,409,948 $ 57,578,586
Reconciliation of contributions per the financial statements    
Contributions per the financial statements 5,368,375  
Add: Employer's contributions receivable at June 30, 2024 1,269,919  
Less: Employer's contributions receivable at June 30, 2025 (1,748,566)  
Contributions per Form 5500 $ 4,889,728  
v3.25.3
Subsequent Events (Details) - Southern Bank 401(k) Retirement Plan (the Plan) - Subsequent Events
Sep. 16, 2025
Sep. 15, 2025
EBP, Subsequent Event [Line Items]    
Minimum requisite service period 2 months 1 year
Deferral rate, percentage 3.00%  
Participant loan term 10 years  
v3.25.3
Schedule H Line 4i - Schedule of Assets (Details) - Southern Bank 401(k) Retirement Plan (the Plan)
12 Months Ended
Jun. 30, 2025
USD ($)
shares
EBP, Schedule of Asset Held for Investment [Line Items]  
Entity Tax Identification Number 43-0462350
EBP, Plan Number 001
EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution $ 876,590
EBP, Asset Held for Investment $ 70,409,948
American Funds Money Market Fund  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Current Value, Type [Extensible Enumeration] American Funds Money Market Fund
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 2,163,753
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 2,163,753
Mutual funds  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 44,494,883
Southern Missouri Bancorp, Inc. Common Stock (SMBC)  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Current Value, Type [Extensible Enumeration] Southern Missouri Bancorp, Inc. Common Stock (SMBC)
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 417,574
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 22,874,722
Investment, Identifier [Axis]: American Funds 2010 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2010TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 18,615
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 231,388
Investment, Identifier [Axis]: American Funds 2015 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2015TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 11,900
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 156,126
Investment, Identifier [Axis]: American Funds 2020 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2020TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 48,846
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 705,339
Investment, Identifier [Axis]: American Funds 2025 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2025TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 65,791
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,070,427
Investment, Identifier [Axis]: American Funds 2030 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2030TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 159,536
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 2,970,559
Investment, Identifier [Axis]: American Funds 2035 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2035TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 208,855
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 4,304,496
Investment, Identifier [Axis]: American Funds 2040 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2040TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 138,574
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 3,109,608
Investment, Identifier [Axis]: American Funds 2045 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2045TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 97,659
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 2,265,697
Investment, Identifier [Axis]: American Funds 2050 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2050TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 92,975
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 2,125,416
Investment, Identifier [Axis]: American Funds 2055 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2055TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 55,265
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,591,089
Investment, Identifier [Axis]: American Funds 2060 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2060TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 39,483
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 775,058
Investment, Identifier [Axis]: American Funds 2065 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2065TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 21,468
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 412,398
Investment, Identifier [Axis]: American Funds 2070 Target Date Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFunds2070TargetDateFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 409
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 4,913
Investment, Identifier [Axis]: American Funds American Balanced Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsAmericanBalancedFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 44,515
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,629,692
Investment, Identifier [Axis]: American Funds Bond Fund of America R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsBondFundOfAmericaR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 69,499
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 789,511
Investment, Identifier [Axis]: American Funds Fundamental Investors R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsFundamentalInvestorsR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 23,456
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 2,054,053
Investment, Identifier [Axis]: American Funds Growth Fund of America R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsGrowthFundOfAmericaR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 56,926
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 4,618,961
Investment, Identifier [Axis]: American Funds Income Fund of America R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsIncomeFundOfAmericaR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 32,958
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 875,683
Investment, Identifier [Axis]: American Funds Intermediate Bond Fund of America R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsIntermediateBondFundOfAmericaR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 40,401
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 512,291
Investment, Identifier [Axis]: American Funds Investment Company of America R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsInvestmentCompanyOfAmericaR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 59,554
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 3,733,460
Investment, Identifier [Axis]: American Funds New Perspective Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsNewPerspectiveFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 25,060
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,714,615
Investment, Identifier [Axis]: American Funds New World Fund R4  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:AmericanFundsNewWorldFundR4Member
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Asset Held for Investment, Party-in-Interest [true false] true
EBP, Investment, Number of Shares | shares 10,467
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 924,172
Investment, Identifier [Axis]: Fidelity Advisor Financials A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:FidelityAdvisorFinancialsMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 3,365
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 127,091
Investment, Identifier [Axis]: Fidelity Advisor Growth Opportunities A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:FidelityAdvisorGrowthOpportunitiesMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 5,764
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,113,100
Investment, Identifier [Axis]: Fidelity Advisor Technology A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:FidelityAdvisorTechnologyMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 5,924
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 757,126
Investment, Identifier [Axis]: Franklin Income Fund A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:FranklinIncomeFundMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 96,410
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 232,349
Investment, Identifier [Axis]: Invesco Comstock A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:InvescoComstockMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 14,200
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 432,964
Investment, Identifier [Axis]: Invesco Small Cap Value A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:InvescoSmallCapValueMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 8,335
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 196,288
Investment, Identifier [Axis]: Ishares S&P 500 Index A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:IsharesSP500IndexMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 1,045
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 758,653
Investment, Identifier [Axis]: Putnam Large Cap Growth A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:PutnamLargeCapGrowthMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 14,058
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,021,564
Investment, Identifier [Axis]: Putnam Small Cap Growth Fund A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:PutnamSmallCapGrowthFundMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 19,396
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,452,187
Investment, Identifier [Axis]: Victory Sycamore Established Value A  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Issuer Name [Extensible Enumeration] smbc:VictorySycamoreEstablishedValueMember
EBP, Investment, Current Value, Type [Extensible Enumeration] Mutual funds
EBP, Investment, Number of Shares | shares 40,313
EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value $ 1,828,609
Maximum [Member]  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Interest Rate 9.50%
Minimum [Member]  
EBP, Schedule of Asset Held for Investment [Line Items]  
EBP, Investment, Interest Rate 4.25%