UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWashington, D.C. 20549 FORM10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period endedMarch 31, 2026 or ☐TRANSITION REPORT PURSUANT TO SECTION13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period fromto Commission File Number: 001-35589 FS BANCORP,INC.(Exact name of registrant as specified in its charter) 45-4585178 (State or other jurisdiction of incorporation or organization)(IRS Employer Identification No.) 6920 220th Street SW, Mountlake Terrace,Washington98043(Address of principal executive offices; Zip Code) (425) 771‑5299 (Registrant’s telephone number, including area code) None (Former name, former address and former fiscalyear, if changed since last report) Securities registered pursuant to Section 12(b) of the Act: Indicate by check mark whether the registrant (1)has filed all reports required to be filed by Section13 or 15(d)of the SecuritiesExchange Act of 1934 during the preceding 12months (or for such shorter period that the registrant was required to file suchreports), and (2)has been subject to such filing requirements for the past 90days.Yes☒No☐ Indicate by check mark whether the registrant has submitted electronically, every Interactive Data File required to be submittedpursuant to Rule405 of Regulation S-T (§232.405 of this chapter) during the preceding 12months (or for such shorter period thatthe registrant was required to submit such files).Yes☒No☐ Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smallerreporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smallerreporting company” and “emerging growth company” in Rule12b‑2 of the Exchange Act. Accelerated filer☒Smaller reporting company☐ Large accelerated filer☐Non-accelerated filer☐Emerging growth company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period forcomplying with any new or revised financial accounting standards provided pursuant to Section13(a)of the Exchange Act.☐ Indicate by check mark whether the registrant is a shell company (as defined in Rule12b‑2 of the Exchange Act).Yes☐No☒ Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date: As ofMay 5, 2026, there were 5,414,542 outstanding shares of the registrant’s common stock. FS Bancorp,Inc.Form10‑QTable of Contents FINANCIAL INFORMATION Item1.Financial StatementsConsolidated Balance Sheets at March 31, 2026 (Unaudited) and December31, 20253Consolidated Statements of Income for the ThreeMonths Ended March 31, 2026and 2025(Unaudited)4Consolidated Statements of Comprehensive Incomefor the Three Months Ended March 31, 2026and 2025 (Unaudited)5Consolidated Statements of Changes in Stockholders’Equity for the Three Months Ended March31, 2026 and 2025 (Unaudited)6Consolidated Statements of Cash Flows for the Three Months Ended March 31, 2026 and 2025(Unaudited)7-8Notesto Consolidated Financial Statements9-44Item2.Management’s Discussion and Analysis of Financial Condition and Results of Operations46-56Item3.Quantitative and Qualitative Disclosures About Market Risk56Item4.Controls and Procedures56PARTIIOTHER INFORMATION57Item1.Legal Proceedings57Item1A.Risk Factors57Item2.Unregistered Sales of Equity Securities and Use of Proceeds57Item3.Defaults Upon Senior Securities58Item4.Mine Safety Disclosures58Item5.Other Information58Item6.Exhibits59SIGNATURES60 When we refer to “FS Bancorp” in this report, we are referring to FS Bancorp,Inc. When we refer to “Bank” or “1st SecurityBank” in this report, we are referring to 1st Security Bank of Washington, the wholly owned subsidiary of FS Bancorp. As used inthis report, the terms “we,” “our,” “us,” and “Company” refer to FS Bancorp, Inc. and its consolidated subsidiary, 1st SecurityBank of Washington, unless the context indicates otherwise. FS BANCORP,INC. AND SUBSIDIARYCONSOLIDATED BALANCE SHEETS (In thousands, except shares and per share amounts) (Unaudited) FS BANCORP,INC. AND SUBSIDIARYCONSOLIDATED STATEMENTS OF INCOME(In thousands, except shares and per share amounts) (Unaudited) FS BANCORP,INC. AND SUBSIDIARYCONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME(In thousands)(Unaudited) Three Months EndedMarch 31,20262025Net income$7,830$8,021Other comprehensive income:Securities available-for-sale:Unrealized (loss) gain during period(1,407)3,496Income tax benefit (provision) related to unrealized gain303(752)Derivative financial instruments:Unrealized derivative gain (loss) during period1,750(2,423)Income tax (provision) benefit related to unrealized derivative gain(376)514Reclassification adjustment for realized gain, net included in net income(237)(871)Income tax provision relat