Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Five Star Bank (the “Bank”) was chartered on October 26, 1999 and began operations on December 20, 1999. Five Star Bancorp (“Bancorp” or the “Company”) was incorporated on September 16, 2002 and subsequently obtained approval from the Board of Governors of the Federal Reserve System (the “Federal Reserve”) to become a bank holding company in connection with its acquisition of the Bank. The Company became the sole shareholder of the Bank on June 2, 2003 in a statutory merger, pursuant to which each outstanding share of the Bank’s common stock was exchanged for one share of common stock of the Company. The Company, through the Bank, provides a broad range of banking products and services to customers who are predominately small and medium-sized businesses, professionals, and individuals residing in the Northern California region. The Company’s primary loan products are commercial real estate loans, land development loans, construction loans, and operating lines of credit, and its primary deposit products are checking accounts, savings accounts, money market accounts, and term certificate accounts. The Bank currently has nine branch offices in Roseville, Natomas, Rancho Cordova, Redding, Elk Grove, Chico, Yuba City, San Francisco, and Walnut Creek, with a tenth branch opening in Lodi in July 2026.
Basis of Financial Statement Presentation and Consolidation and Emerging Growth Company	Basis of Financial Statement Presentation and Consolidation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) as contained within the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”), including Accounting Standards Updates (“ASU”), and the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Regulation S-X. These interim unaudited consolidated financial statements reflect all adjustments (consisting solely of normal recurring adjustments and accruals) which, in the opinion of management, are necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in shareholders’ equity, and cash flows for the interim periods presented. These unaudited consolidated financial statements have been prepared on a basis consistent with, and should be read in conjunction with, the audited consolidated financial statements as of and for the year ended December 31, 2025, and the notes thereto, included in the Company’s Annual Report on Form 10-K (the “2025 Annual Report on Form 10-K”), which was filed with the SEC on February 27, 2026. The unaudited consolidated financial statements include Bancorp and its wholly owned subsidiary, the Bank. All significant intercompany transactions and balances are eliminated in consolidation. The results of operations for the three and six months ended June 30, 2026 are not necessarily indicative of the results of operations that may be expected for any other interim period or for the year ending December 31, 2026. The Company’s accounting and reporting policies conform to GAAP and to general practices within the banking industry. Emerging Growth Company The Company qualifies as an emerging growth company as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and, as such, may take advantage of specified reduced reporting requirements and deferred adoption dates for accounting standards, and is relieved of other significant requirements that are otherwise generally applicable to other public companies. The Company will remain an emerging growth company until the last day of the fiscal year following the fifth anniversary of its initial public offering (“IPO”) date of May 5, 2021, unless one of the following occurs: (i) total annual gross revenues are $1.235 billion or more; (ii) the Company issues more than $1.0 billion in non-convertible debt; or (iii) the Company becomes a large accelerated filer with a public float of more than $0.7 billion, as measured at June 30 annually.
Segments	Segments The Company has one reportable operating segment: banking. The banking segment derives its revenues through the Bank, which provides a broad range of banking products and services to customers who are predominantly small and middle-market businesses, professionals, and individuals primarily in the Northern California region. The Company manages the business activities on a consolidated basis. The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer, who reviews financial information presented on a consolidated basis. The CODM assesses performance for the operating segment and decides how to allocate resources based on net income that also is reported on the income statement as consolidated net income. The measure of segment assets is reported on the balance sheet as total consolidated assets. These financial metrics are used by the CODM to make key operating decisions, such as determination of the rate at which the Company seeks to grow, loan and deposit pricing, and the allocation of budget for non-interest expenses. Net income is used to monitor budget versus actual results. Discrete financial information is not available other than on a Company-wide basis.
Recently Issued Accounting Standards, Accounting Standards Adopted and Accounting Standards Issued But Not Yet Adopted	Recently Issued Accounting Standards The following information reflects recent accounting standards that have been adopted or are pending adoption by the Company. The Company qualifies as an emerging growth company and, as such, has elected not to opt out of the extended transition period for complying with new or revised accounting standards and is not subject to the new or revised accounting standards applicable to public companies during the extended transition period. However, we may early adopt certain accounting standards, as the JOBS Act does not preclude an emerging growth company from adopting a new or revised accounting standard earlier than the time that such standard applies to private companies to the extent early adoption is permitted. Our early adoption of ASU 2023-09 was voluntary and does not represent an irrevocable election to opt out of the extended transition period for all standards. The accounting standards discussed below indicate effective dates for the Company as an emerging growth company using the extended transition period. Accounting Standards Adopted in 2026 In December 2023, the FASB issued ASU 2023-09, which enhances the transparency and decision usefulness of income tax disclosures. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. Entities are also required to disclose income/(loss) from continuing operations before income tax expense/(benefit) disaggregated between domestic and foreign operations, as well as income tax expense/(benefit) from continuing operations disaggregated by federal, state, and foreign operations. ASU 2023-09 is effective for fiscal years beginning after December 15, 2025, including interim periods within those fiscal years, for emerging growth companies that have elected not to opt out of the extended transition period. The Company elected to early adopt ASU 2023-09 for the fiscal year ended December 31, 2025, which did not have a significant impact on the Company’s consolidated financial statements. The Company’s early adoption of ASU 2023-09 was voluntary and does not represent an irrevocable election to opt out of the extended transition period for all standards. The Company has updated its income tax disclosures in accordance with ASU 2023-09, which primarily enhances transparency regarding income tax expense and related items. In March 2024, the FASB issued ASU 2024-02, Codification Improvements - Amendments to Remove References to the Concepts Statements (“ASU 2024-02”). ASU 2024-02 contains amendments to the ASC that remove references to various Concepts Statements. In most instances, the references are extraneous and not required to understand or apply the guidance. In other instances, the references were used in prior Statements to provide guidance in certain topical areas. FASB Concepts Statements are nonauthoritative. Removing all references to Concepts Statements in the guidance is intended to simplify the ASC and draw a distinction between authoritative and nonauthoritative literature. ASU 2024-02 is effective January 1, 2026 for emerging growth companies electing not to opt out of the extended transition period and has not had a significant impact on the Company’s consolidated financial statements. Accounting Standards Issued But Not Yet Adopted In October 2023, the FASB issued ASU No. 2023-06, Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”), amending disclosure or presentation requirements related to various subtopics in the FASB’s ASC. ASU 2023-06 was issued in response to the SEC’s initiative to update and simplify disclosure requirements. The SEC identified 27 disclosure requirements that were incremental to those in the ASC and referred them to the FASB for potential incorporation into GAAP. To avoid duplication, the SEC intended to eliminate those disclosure requirements from existing SEC regulations as the FASB incorporated them into the relevant ASC subtopics. ASU 2023-06 adds 14 of the 27 identified disclosure or presentation requirements to the ASC. ASU 2023-06 is to be applied prospectively, and early adoption is prohibited. For reporting entities subject to the SEC’s existing disclosure requirements, the effective dates of ASU 2023-06 will be the date on which the SEC’s removal of that related disclosure requirement from Regulation S-X or Regulation S-K becomes effective. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the related amendment will be removed from the ASC and will not become effective for any entities. ASU 2023-06 is not expected to have a significant impact on the Company’s consolidated financial statements. On November 4, 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“Subtopic 220-40”): Disaggregation of Income Statement Expenses (“ASU 2024-03”) and in January 2025 the FASB issued ASU 2025-01, Clarifying the Effective Date. This standard responds to investor input by requiring public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the notes to the financial statements. This standard is effective for all entities that are subject to Subtopic 220-40, for annual periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027, but early adoption is permitted. ASU 2024-03 is not expected to have a significant impact on the Company’s consolidated financial statements.
Reclassifications	Reclassifications Certain amounts reported in previous consolidated financial statements have been reclassified to conform to current period presentation. These reclassifications did not affect previously reported amounts of net income, total assets, or total shareholders’ equity.
Earnings per Share (“EPS”)	Earnings per Share (“EPS”) Basic EPS is net income divided by the weighted average number of common shares outstanding during the period less average unvested restricted stock awards (“RSAs”). Diluted EPS includes the dilutive effect of additional potential common shares related to unvested RSAs and unvested performance-based restricted stock awards (“PSUs”) using the treasury stock method. The Company has two forms of outstanding common stock: common stock and unvested RSAs. Holders of unvested RSAs receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings, and therefore the RSAs are considered participating securities. However, under the two-class method, the difference in EPS is not significant for these participating securities. PSUs represent the right to receive shares of common stock upon the achievement of specified performance conditions over a defined performance period. Unlike RSAs, PSUs do not carry voting rights or dividend rights prior to vesting, and the number of shares ultimately issued may range from zero to a maximum payout factor depending on the level of performance achieved relative to pre-established targets. PSUs are included in the diluted EPS calculation using the treasury stock method only to the extent the applicable performance conditions have been met or are considered probable of being met as of the end of the reporting period.

Basis of Presentation and Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Five Star Bank (the “Bank”) was chartered on October 26, 1999 and began operations on December 20, 1999. Five Star Bancorp (“Bancorp” or the “Company”) was incorporated on September 16, 2002 and subsequently obtained approval from the Board of Governors of the Federal Reserve System (the “Federal Reserve”) to become a bank holding company in connection with its acquisition of the Bank. The Company became the sole shareholder of the Bank on June 2, 2003 in a statutory merger, pursuant to which each outstanding share of the Bank’s common stock was exchanged for one share of common stock of the Company.

The Company, through the Bank, provides a broad range of banking products and services to customers who are predominately small and medium-sized businesses, professionals, and individuals residing in the Northern California region. The Company’s primary loan products are commercial real estate loans, land development loans, construction loans, and operating lines of credit, and its primary deposit products are checking accounts, savings accounts, money market accounts, and term certificate accounts. The Bank currently has nine branch offices in Roseville, Natomas, Rancho Cordova, Redding, Elk Grove, Chico, Yuba City, San Francisco, and Walnut Creek, with a tenth branch opening in Lodi in July 2026.

Basis of Financial Statement Presentation and Consolidation and Emerging Growth Company

Basis of Financial Statement Presentation and Consolidation

The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) as contained within the Financial Accounting Standards Board’s (“FASB”) Accounting Standards Codification (“ASC”), including Accounting Standards Updates (“ASU”), and the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Regulation S-X. These interim unaudited consolidated financial statements reflect all adjustments (consisting solely of normal recurring adjustments and accruals) which, in the opinion of management, are necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in shareholders’ equity, and cash flows for the interim periods presented. These unaudited consolidated financial statements have been prepared on a basis consistent with, and should be read in conjunction with, the audited consolidated financial statements as of and for the year ended December 31, 2025, and the notes thereto, included in the Company’s Annual Report on Form 10-K (the “2025 Annual Report on Form 10-K”), which was filed with the SEC on February 27, 2026.

The unaudited consolidated financial statements include Bancorp and its wholly owned subsidiary, the Bank. All significant intercompany transactions and balances are eliminated in consolidation.

The results of operations for the three and six months ended June 30, 2026 are not necessarily indicative of the results of operations that may be expected for any other interim period or for the year ending December 31, 2026.

The Company’s accounting and reporting policies conform to GAAP and to general practices within the banking industry.

Emerging Growth Company

The Company qualifies as an emerging growth company as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), and, as such, may take advantage of specified reduced reporting requirements and deferred adoption dates for accounting standards, and is relieved of other significant requirements that are otherwise generally applicable to other public companies. The Company will remain an emerging growth company until the last day of the fiscal year following the fifth anniversary of its initial public offering (“IPO”) date of May 5, 2021, unless one of the following occurs: (i) total annual gross revenues are $1.235 billion or more; (ii) the Company issues more than $1.0 billion in non-convertible debt; or (iii) the Company becomes a large accelerated filer with a public float of more than $0.7 billion, as measured at June 30 annually.

Segments

The Company has one reportable operating segment: banking. The banking segment derives its revenues through the Bank, which provides a broad range of banking products and services to customers who are predominantly small and middle-market businesses, professionals, and individuals primarily in the Northern California region. The Company manages the business activities on a consolidated basis.

The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer, who reviews financial information presented on a consolidated basis. The CODM assesses performance for the operating segment and decides how to allocate resources based on net income that also is reported on the income statement as consolidated net income. The measure of segment assets is reported on the balance sheet as total consolidated assets.

These financial metrics are used by the CODM to make key operating decisions, such as determination of the rate at which the Company seeks to grow, loan and deposit pricing, and the allocation of budget for non-interest expenses. Net income is

used to monitor budget versus actual results. Discrete financial information is not available other than on a Company-wide basis.

Recently Issued Accounting Standards, Accounting Standards Adopted and Accounting Standards Issued But Not Yet Adopted

Recently Issued Accounting Standards

The following information reflects recent accounting standards that have been adopted or are pending adoption by the Company. The Company qualifies as an emerging growth company and, as such, has elected not to opt out of the extended transition period for complying with new or revised accounting standards and is not subject to the new or revised accounting standards applicable to public companies during the extended transition period. However, we may early adopt certain accounting standards, as the JOBS Act does not preclude an emerging growth company from adopting a new or revised accounting standard earlier than the time that such standard applies to private companies to the extent early adoption is permitted. Our early adoption of ASU 2023-09 was voluntary and does not represent an irrevocable election to opt out of the extended transition period for all standards. The accounting standards discussed below indicate effective dates for the Company as an emerging growth company using the extended transition period.

Accounting Standards Adopted in 2026

In December 2023, the FASB issued ASU 2023-09, which enhances the transparency and decision usefulness of income tax disclosures. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. Entities are also required to disclose income/(loss) from continuing operations before income tax expense/(benefit) disaggregated between domestic and foreign operations, as well as income tax expense/(benefit) from continuing operations disaggregated by federal, state, and foreign operations. ASU 2023-09 is effective for fiscal years beginning after December 15, 2025, including interim periods within those fiscal years, for emerging growth companies that have elected not to opt out of the extended transition period. The Company elected to early adopt ASU 2023-09 for the fiscal year ended December 31, 2025, which did not have a significant impact on the Company’s consolidated financial statements. The Company’s early adoption of ASU 2023-09 was voluntary and does not represent an irrevocable election to opt out of the extended transition period for all standards. The Company has updated its income tax disclosures in accordance with ASU 2023-09, which primarily enhances transparency regarding income tax expense and related items.

In March 2024, the FASB issued ASU 2024-02, Codification Improvements - Amendments to Remove References to the Concepts Statements (“ASU 2024-02”). ASU 2024-02 contains amendments to the ASC that remove references to various Concepts Statements. In most instances, the references are extraneous and not required to understand or apply the guidance. In other instances, the references were used in prior Statements to provide guidance in certain topical areas. FASB Concepts Statements are nonauthoritative. Removing all references to Concepts Statements in the guidance is intended to simplify the ASC and draw a distinction between authoritative and nonauthoritative literature. ASU 2024-02 is effective January 1, 2026 for emerging growth companies electing not to opt out of the extended transition period and has not had a significant impact on the Company’s consolidated financial statements.

Accounting Standards Issued But Not Yet Adopted

In October 2023, the FASB issued ASU No. 2023-06, Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”), amending disclosure or presentation requirements related to various subtopics in the FASB’s ASC. ASU 2023-06 was issued in response to the SEC’s initiative to update and simplify disclosure requirements. The SEC identified 27 disclosure requirements that were incremental to those in the ASC and referred them to the FASB for potential incorporation into GAAP. To avoid duplication, the SEC intended to eliminate those disclosure requirements from existing SEC regulations as the FASB incorporated them into the relevant ASC subtopics. ASU 2023-06 adds 14 of the 27 identified disclosure or presentation requirements to the ASC. ASU 2023-06 is to be applied prospectively, and early adoption is prohibited. For reporting entities subject to the SEC’s existing disclosure requirements, the effective dates of ASU 2023-06 will be the date on which the SEC’s removal of that related disclosure requirement from Regulation S-X or Regulation S-K becomes effective. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the related amendment will be removed from the ASC and will not become effective for any entities. ASU 2023-06 is not expected to have a significant impact on the Company’s consolidated financial statements.

On November 4, 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (“Subtopic 220-40”): Disaggregation of Income Statement Expenses (“ASU 2024-03”) and in January 2025 the FASB issued ASU 2025-01, Clarifying the Effective Date. This standard responds to investor input by requiring public companies to disclose, in interim and annual reporting periods, additional information about certain expenses in the notes to the financial statements. This standard is effective for all entities that are subject to Subtopic 220-40, for annual periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027, but early adoption is permitted. ASU 2024-03 is not expected to have a significant impact on the Company’s consolidated financial statements.

Reclassifications

Certain amounts reported in previous consolidated financial statements have been reclassified to conform to current period presentation. These reclassifications did not affect previously reported amounts of net income, total assets, or total shareholders’ equity.

Earnings per Share (“EPS”)

Basic EPS is net income divided by the weighted average number of common shares outstanding during the period less average unvested restricted stock awards (“RSAs”). Diluted EPS includes the dilutive effect of additional potential common shares related to unvested RSAs and unvested performance-based restricted stock awards (“PSUs”) using the treasury stock method. The Company has two forms of outstanding common stock: common stock and unvested RSAs. Holders of unvested RSAs receive non-forfeitable dividends at the same rate as common shareholders and they both share equally in undistributed earnings, and therefore the RSAs are considered participating securities. However, under the two-class method, the difference in EPS is not significant for these participating securities. PSUs represent the right to receive shares of common stock upon the achievement of specified performance conditions over a defined performance period. Unlike RSAs, PSUs do not carry voting rights or dividend rights prior to vesting, and the number of shares ultimately issued may range from zero to a maximum payout factor depending on the level of performance achieved relative to pre-established targets. PSUs are included in the diluted EPS calculation using the treasury stock method only to the extent the applicable performance conditions have been met or are considered probable of being met as of the end of the reporting period.