Basis of Presentation (Policies)	3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial information is unaudited and has been prepared from the consolidated financial statements of Sound Financial Bancorp, Inc, and its wholly owned subsidiaries, Sound Community Bank and Sound Community Insurance Agency, Inc. References in this document to “Sound Financial Bancorp” refer to Sound Financial Bancorp, Inc. and references to the “Bank” refer to Sound Community Bank. References to “we,” “us,” and “our” or the “Company” refer to Sound Financial Bancorp, the Bank and Sound Community Insurance Agency, Inc., collectively, unless the context otherwise requires. These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information and disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the SEC on March 18, 2025 (“2024 Form 10-K”). The results for the interim periods are not necessarily indicative of results for a full year or any other future period. We have not made any changes in our significant accounting policies from those disclosed in the 2024 Form 10-K.
Accounting Pronouncements Recently Issued or Adopted	Accounting Pronouncements Recently Issued or Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which expands disclosures about a public entity’s reportable segments and requires more enhanced information about a reportable segment’s expenses, interim segment profit or loss, and how a public entity’s chief operating decision maker uses reported segment profit or loss information in assessing segment performance and allocating resources. The Company adopted this ASU on January 1, 2024. ASU 2023-07 did not have an impact on the Company's financial position or results of operation as it impacts disclosures only. The adoption of this ASU did not have a material impact on the Company’s disclosures as the Company operates under one segment. In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures. This ASU requires public business entities to annually (1) disclose specific categories in the rate reconciliation and (2) provide additional information for reconciling items that meet a quantitative threshold. This ASU was released in response to stakeholder feedback indicating that the existing income tax disclosures should be enhanced to provide information to better assess how an entity’s operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. This ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2024, with early adoption permitted. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated results of operations, financial position or cash flows. In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40), which will change the disclosures about a public business entity’s expenses and address requests from investors for more detailed information about the types of expenses (for example, employee compensation, depreciation and amortization) in expense captions. This ASU’s amendments are effective for public business entities for annual reporting periods beginning after December 15, 2026, and for interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of this guidance.
Fair Value Measurements	Fair Value Measurements The Company determines the fair values of its financial instruments based on the requirements established in ASC 820, Fair Value Measurements (“ASC 820”), which provides a framework for measuring fair value in accordance with U.S. GAAP and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 defines fair values for financial instruments as the exit price, the price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date under current market conditions. The Company’s fair values for financial instruments at March 31, 2025 and December 31, 2024 were determined based on these requirements. The following methods and assumptions were used to estimate the fair value of the Company’s financial instruments: Cash and cash equivalents - The estimated fair value is equal to the carrying amount. Available-for-sale securities – AFS securities are recorded at fair value based on quoted market prices, if available (Level 1). If quoted market prices are not available, management utilizes third-party pricing services or broker quotations from dealers in the specific instruments (Level 2). Level 2 securities include those traded on an active exchange, as well as U.S. government securities. Held-to-maturity securities – The fair value is based on quoted market prices, if available. If quoted market prices are not available, management utilizes third-party pricing services or broker quotations from dealers in the specific instruments. Level 2 securities include those traded on an active exchange, as well as U.S. government securities. Loans held-for-sale - The fair value of fixed-rate one-to-four family loans is based on whole loan forward prices obtained from government sponsored enterprises. Loans held-for-portfolio - The estimated fair value of loans held-for-portfolio consists of a credit adjustment to reflect the estimated adjustment to the carrying value of the loans due to credit-related factors and a yield adjustment to reflect the estimated adjustment to the carrying value of the loans due to a differential in yield between the portfolio loan yields and estimated current market rate yields on loans with similar characteristics. The estimated fair values of loans held-for-portfolio reflect exit price assumptions. The liquidity premiums/discounts are part of the valuation for exit pricing. Mortgage servicing rights –The fair value of MSRs is determined through a discounted cash flow analysis, which uses interest rates, prepayment speeds, discount rates, and delinquency rate assumptions as inputs. Time deposits - The estimated fair value of time deposits is based on the difference between interest rates paid on the Company’s time deposits and current market rates for time deposits with comparable characteristics. Borrowings - The fair value of borrowings is estimated using the contractual cash flows of each debt instrument discounted using the Company’s current incremental borrowing rates for similar types of borrowing arrangements. Subordinated notes - The fair value of subordinated notes is estimated using discounted cash flows based on current borrowing rates for similar long-term debt instruments with similar terms and remaining time to maturity. A description of the valuation methodologies used for collateral dependent loans, OREO and repossessed assets and off-balance sheet loan commitments is as follows: Collateral dependent loans - The fair value of collateral dependent loans is based on the current appraised value of the collateral less estimated costs to sell. OREO and repossessed assets – The fair value of OREO and repossessed assets is based on the current appraised value of the collateral less estimated costs to sell. Off-balance sheet financial instruments - The fair value of off-balance sheet financial instruments, which consisted entirely of loan commitments at March 31, 2025 and December 31, 2024, is estimated based on fees charged to others to enter into similar agreements, taking into account the remaining terms of the agreements and credit standing of the Company’s clients. The estimated fair value of these commitments was not significant at March 31, 2025 and December 31, 2024. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the lowest level of inputs that is significant to the measurement is used to determine the hierarchy for the entire asset or liability. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with the Company’s quarterly valuation process. There were no transfers between levels during the three months ended March 31, 2025 and 2024.

Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The accompanying financial information is unaudited and has been prepared from the consolidated financial statements of Sound Financial Bancorp, Inc, and its wholly owned subsidiaries, Sound Community Bank and Sound Community Insurance Agency, Inc. References in this document to “Sound Financial Bancorp” refer to Sound Financial Bancorp, Inc. and references to the “Bank” refer to Sound Community Bank. References to “we,” “us,” and “our” or the “Company” refer to Sound Financial Bancorp, the Bank and Sound Community Insurance Agency, Inc., collectively, unless the context otherwise requires.

These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information and disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the SEC on March 18, 2025 (“2024 Form 10-K”). The results for the interim periods are not necessarily indicative of results for a full year or any other future period.

We have not made any changes in our significant accounting policies from those disclosed in the 2024 Form 10-K.

Accounting Pronouncements Recently Issued or Adopted

In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which expands disclosures about a public entity’s reportable segments and requires more enhanced information about a reportable segment’s expenses, interim segment profit or loss, and how a public entity’s chief operating decision maker uses reported segment profit or loss information in assessing segment performance and allocating resources. The Company adopted this ASU on January 1, 2024. ASU 2023-07 did not have an impact on the Company's financial position or results of operation as it impacts disclosures only. The adoption of this ASU did not have a material impact on the Company’s disclosures as the Company operates under one segment.

In December 2023, the FASB issued ASU 2023-09, Improvements to Income Tax Disclosures. This ASU requires public business entities to annually (1) disclose specific categories in the rate reconciliation and (2) provide additional information for reconciling items that meet a quantitative threshold. This ASU was released in response to stakeholder feedback indicating that the existing income tax disclosures should be enhanced to provide information to better assess how an entity’s operations and related tax risks and tax planning and operational opportunities affect its tax rate and prospects for future cash flows. This ASU’s amendments are effective for public business entities for annual periods beginning after December 15, 2024, with early adoption permitted. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated results of operations, financial position or cash flows.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40), which will change the disclosures about a public business entity’s expenses and address requests from investors for more detailed information about the types of expenses (for example, employee compensation, depreciation and amortization) in expense captions. This ASU’s amendments are effective for public business entities for annual reporting periods beginning after December 15, 2026, and for interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of this guidance.

Fair Value Measurements

The Company determines the fair values of its financial instruments based on the requirements established in ASC 820, Fair Value Measurements (“ASC 820”), which provides a framework for measuring fair value in accordance with U.S. GAAP and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 defines fair values for financial instruments as the exit price, the price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date under current market conditions. The Company’s fair values for financial instruments at March 31, 2025 and December 31, 2024 were determined based on these requirements.

The following methods and assumptions were used to estimate the fair value of the Company’s financial instruments:

Cash and cash equivalents - The estimated fair value is equal to the carrying amount.

Available-for-sale securities – AFS securities are recorded at fair value based on quoted market prices, if available (Level 1). If quoted market prices are not available, management utilizes third-party pricing services or broker quotations from dealers in the specific instruments (Level 2). Level 2 securities include those traded on an active exchange, as well as U.S. government securities.

Held-to-maturity securities – The fair value is based on quoted market prices, if available. If quoted market prices are not available, management utilizes third-party pricing services or broker quotations from dealers in the specific instruments. Level 2 securities include those traded on an active exchange, as well as U.S. government securities.

Loans held-for-sale - The fair value of fixed-rate one-to-four family loans is based on whole loan forward prices obtained from government sponsored enterprises.

Loans held-for-portfolio - The estimated fair value of loans held-for-portfolio consists of a credit adjustment to reflect the estimated adjustment to the carrying value of the loans due to credit-related factors and a yield adjustment to reflect the estimated adjustment to the carrying value of the loans due to a differential in yield between the portfolio loan yields and estimated current market rate yields on loans with similar characteristics. The estimated fair values of loans held-for-portfolio reflect exit price assumptions. The liquidity premiums/discounts are part of the valuation for exit pricing.

Mortgage servicing rights –The fair value of MSRs is determined through a discounted cash flow analysis, which uses interest rates, prepayment speeds, discount rates, and delinquency rate assumptions as inputs.

Time deposits - The estimated fair value of time deposits is based on the difference between interest rates paid on the Company’s time deposits and current market rates for time deposits with comparable characteristics.

Borrowings - The fair value of borrowings is estimated using the contractual cash flows of each debt instrument discounted using the Company’s current incremental borrowing rates for similar types of borrowing arrangements.

Subordinated notes - The fair value of subordinated notes is estimated using discounted cash flows based on current borrowing rates for similar long-term debt instruments with similar terms and remaining time to maturity.

A description of the valuation methodologies used for collateral dependent loans, OREO and repossessed assets and off-balance sheet loan commitments is as follows:

Collateral dependent loans - The fair value of collateral dependent loans is based on the current appraised value of the collateral less estimated costs to sell.

OREO and repossessed assets – The fair value of OREO and repossessed assets is based on the current appraised value of the collateral less estimated costs to sell.

Off-balance sheet financial instruments - The fair value of off-balance sheet financial instruments, which consisted entirely of loan commitments at March 31, 2025 and December 31, 2024, is estimated based on fees charged to others to enter into similar agreements, taking into account the remaining terms of the agreements and credit standing of the Company’s clients. The estimated fair value of these commitments was not significant at March 31, 2025 and December 31, 2024.

In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the lowest level of inputs that is significant to the measurement is used to determine the hierarchy for the entire asset or liability. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with the Company’s quarterly valuation process. There were no transfers between levels during the three months ended March 31, 2025 and 2024.