Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2026
Accounting Policies [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, 2025, as filed with the SEC on March 18, 2026 (“2025 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 2025 Form 10-K.
Accounting Pronouncements Recently Issued or Adopted	Accounting Pronouncements Recently Issued or Adopted In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“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 is 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 on its disclosures and expects adoption will result in a more disaggregated presentation of expense line items in its financial statement footnotes. In September 2025, the FASB issued ASU No. 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software, which simplifies and modernizes the accounting for internal-use software by removing prescriptive project stage guidance and introducing a new capitalization threshold. Under the revised standard, software development costs are capitalized when management authorizes and commits funding for the project, and it is probable the software will be completed and used as intended. This ASU is effective for annual and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company does not expect the adoption of this guidance to have a significant impact on the Company’s consolidated financial statements. In November 2025, the FASB issued ASU 2025‑08, Financial Instruments - Credit Losses (Topic 326): Purchased Loans, which expands the scope of the “gross‑up” method, formerly applicable only to purchased credit‑deteriorated ("PCD") assets, to include acquired non‑PCD loans that meet certain criteria, now referred to as “purchased seasoned loans” (PSLs). Under this model, an allowance for expected credit losses is recognized at acquisition, offsetting the loan’s amortized cost basis, thereby eliminating the day-one credit‑loss expense previously required for non‑PCD assets. PSLs are defined as non‑PCD loans acquired either (i) through a business combination, or (ii) purchased more than 90 days after origination when the acquirer was not involved in origination. This ASU is effective on a prospective basis for loans acquired on or after the adoption date, which is for interim and annual reporting periods beginning after December 15, 2026. Early adoption is permitted. This ASU is not expected to have a significant impact on the Company’s consolidated financial statements. In December 2025, the FASB issued ASU 2025‑11, Interim Reporting (Topic 270): Narrow‑Scope Improvements, which clarifies and enhances guidance under ASC 270 on interim financial reporting by (i) clarifying the scope of ASC 270 such that it now explicitly applies only to entities that issue complete interim financial statements and related notes under U.S. GAAP, (ii) establishing clear guidance on the form of interim financial statements and notes, incorporating a comprehensive list of required interim disclosures drawn from across the ASC, and (iii) introducing a requirement to disclose material events and changes occurring after the end of the last annual period that could impact interim results. This ASU is effective for interim and annual reporting periods beginning after December 15, 2027. Early adoption is permitted. This ASU is not expected to have a significant impact on the Company’s consolidated financial statements.
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 entities to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 defines fair value as the exit price that would be received to sell an asset or paid to transfer a liability in the principal (or most advantageous) market in an orderly transaction between market participants at the measurement date. The Company’s fair values for financial instruments at June 30, 2026 and December 31, 2025 were determined based on this guidance. 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 equals the carrying amount. Available-for-sale securities – The fair value is 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 (Level 2). Level 2 measurements generally include U.S. government and agency securities and other securities valued using observable market inputs. Held-to-maturity securities – The estimated fair value is determined using quoted market prices, if available. If quoted market prices are not available, management utilizes third-party pricing services or broker quotations. Equity investments - Equity investments consist of securities without readily determinable fair values and are accounted for under the measurement alternative in accordance with ASC 321. Accordingly, these investments are carried at cost, less impairment, and adjusted for observable price changes in orderly transactions for identical or similar investments, with any such adjustments or impairment recognized in net income. Loans held-for-sale - The fair value of is based on whole loan forward prices obtained from government-sponsored enterprises. Loans held-for-portfolio - The estimated fair value is determined by applying adjustments for credit-related factors and differences between the contractual yields on the portfolio and current market yields for loans with similar characteristics. The estimated fair value reflects exit price assumptions, including liquidity premiums or discounts. Mortgage servicing rights –The fair value is determined using a discounted cash flow model that incorporated interest rates, prepayment speeds, discount rates, and delinquency assumptions as inputs. Time deposits - The estimated fair value 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 estimated fair value is determined using the contractual cash flows of each debt instrument discounted at the Company’s current incremental borrowing rates for similar types of borrowing arrangements. Subordinated notes - The estimated fair value is determined using the contractual cash flows discounted at 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 estimated fair value is determined using the current appraised value of the collateral, less estimated costs to sell. OREO and repossessed assets – The fair value is determined using the current appraised value of the collateral less estimated costs to sell. Off-balance sheet financial instruments - The estimated fair value, which consisted entirely of loan commitments at June 30, 2026 and December 31, 2025, is determined 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 counterparties. The estimated fair value of these commitments was not significant at June 30, 2026 and December 31, 2025. 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 and six months ended June 30, 2026 and 2025.

Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2026

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, 2025, as filed with the SEC on March 18, 2026 (“2025 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 2025 Form 10-K.

Accounting Pronouncements Recently Issued or Adopted

In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“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 is 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 on its disclosures and expects adoption will result in a more disaggregated presentation of expense line items in its financial statement footnotes.

In September 2025, the FASB issued ASU No. 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software, which simplifies and modernizes the accounting for internal-use software by removing prescriptive project stage guidance and introducing a new capitalization threshold. Under the revised standard, software development costs are capitalized when management authorizes and commits funding for the project, and it is probable the software will be completed and used as intended. This ASU is effective for annual and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company does not expect the adoption of this guidance to have a significant impact on the Company’s consolidated financial statements.

In November 2025, the FASB issued ASU 2025‑08, Financial Instruments - Credit Losses (Topic 326): Purchased Loans, which expands the scope of the “gross‑up” method, formerly applicable only to purchased credit‑deteriorated ("PCD") assets, to include acquired non‑PCD loans that meet certain criteria, now referred to as “purchased seasoned loans” (PSLs). Under this model, an allowance for expected credit losses is recognized at acquisition, offsetting the loan’s amortized cost basis, thereby eliminating the day-one credit‑loss expense previously required for non‑PCD assets. PSLs are defined as non‑PCD loans acquired either (i) through a business combination, or (ii) purchased more than 90 days after origination when the acquirer was not involved in origination. This ASU is effective on a prospective basis for loans acquired on or after the adoption date, which is for interim and annual reporting periods beginning after December 15, 2026. Early adoption is permitted. This ASU is not expected to have a significant impact on the Company’s consolidated financial statements.

In December 2025, the FASB issued ASU 2025‑11, Interim Reporting (Topic 270): Narrow‑Scope Improvements, which clarifies and enhances guidance under ASC 270 on interim financial reporting by (i) clarifying the scope of ASC 270 such that it now explicitly applies only to entities that issue complete interim financial statements and related notes under U.S. GAAP, (ii) establishing clear guidance on the form of interim financial statements and notes, incorporating a comprehensive list of

required interim disclosures drawn from across the ASC, and (iii) introducing a requirement to disclose material events and changes occurring after the end of the last annual period that could impact interim results. This ASU is effective for interim and annual reporting periods beginning after December 15, 2027. Early adoption is permitted. This ASU is not expected to have a significant impact on the Company’s consolidated financial statements.

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 entities to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 defines fair value as the exit price that would be received to sell an asset or paid to transfer a liability in the principal (or most advantageous) market in an orderly transaction between market participants at the measurement date. The Company’s fair values for financial instruments at June 30, 2026 and December 31, 2025 were determined based on this guidance.

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 equals the carrying amount.

Available-for-sale securities – The fair value is 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 (Level 2). Level 2 measurements generally include U.S. government and agency securities and other securities valued using observable market inputs.

Held-to-maturity securities – The estimated fair value is determined using quoted market prices, if available. If quoted market prices are not available, management utilizes third-party pricing services or broker quotations.

Equity investments - Equity investments consist of securities without readily determinable fair values and are accounted for under the measurement alternative in accordance with ASC 321. Accordingly, these investments are carried at cost, less impairment, and adjusted for observable price changes in orderly transactions for identical or similar investments, with any such adjustments or impairment recognized in net income.

Loans held-for-sale - The fair value of is based on whole loan forward prices obtained from government-sponsored enterprises.

Loans held-for-portfolio - The estimated fair value is determined by applying adjustments for credit-related factors and differences between the contractual yields on the portfolio and current market yields for loans with similar characteristics. The estimated fair value reflects exit price assumptions, including liquidity premiums or discounts.

Mortgage servicing rights –The fair value is determined using a discounted cash flow model that incorporated interest rates, prepayment speeds, discount rates, and delinquency assumptions as inputs.

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

Subordinated notes - The estimated fair value is determined using the contractual cash flows discounted at 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 estimated fair value is determined using the current appraised value of the collateral, less estimated costs to sell.

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

Off-balance sheet financial instruments - The estimated fair value, which consisted entirely of loan commitments at June 30, 2026 and December 31, 2025, is determined 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 counterparties. The estimated fair value of these commitments was not significant at June 30, 2026 and December 31, 2025.

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 and six months ended June 30, 2026 and 2025.