Nature of Business and Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2022
Nature of Business and Summary of Significant Accounting Policies
Nature of Business and Summary of Significant Accounting Policies	Note 1— Nature of Business and Summary of Significant Accounting Policies Nature of Banking Activities John Marshall Bancorp, Inc. (the “Company”), headquartered in Reston, Virginia, became the registered bank holding company under the Bank Holding Company Act of 1956 for its wholly-owned subsidiary, John Marshall Bank (the “Bank”), on March 1, 2017. This reorganization was completed through a one-for-one share exchange in which the Bank’s shareholders received one share of voting common stock of the Company in exchange for each share of the Bank’s voting common stock. The Company was formed on April 21, 2016 under the laws of the Commonwealth Virginia. The Bank was formed on April 5, 2005 under the laws of the Commonwealth of Virginia and was chartered as a bank on February 9, 2006, by the Virginia Bureau of Financial Institutions. The Bank is a member of the Federal Reserve System and is subject to the rules and regulations of the Virginia Bureau of Financial Institutions, the Board of Governors of the Federal Reserve System (the “Federal Reserve”) and the Federal Deposit Insurance Corporation (“FDIC”). The Bank opened for business on April 17, 2006 and provides banking services to its customers primarily in the Washington, D.C. metropolitan area. Basis of Presentation The accounting and reporting policies of John Marshall Bancorp, Inc. conform to generally accepted accounting principles in the United States of America (“GAAP”) and reflect practices of the banking industry. The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial reporting and with applicable quarterly reporting regulations of the U.S. Securities and Exchange Commission (“SEC”). They do not include all of the information and notes required by GAAP for complete financial statements. As such, these consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto as of and for the year ending December 31, 2021, included in the Company’s Registration Statement on Form 10, as amended, filed with the SEC on April 18, 2022. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany accounts and transactions between the Company and the Bank have been eliminated. In preparing financial statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the results of operations in these financial statements, have been made. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for any other interim period or for the full year. All amounts and disclosures included in this quarterly report as of December 31, 2021, were derived from the Company’s audited consolidated financial statements. Certain items in the prior period financial statements have been reclassified to conform to the current presentation. These reclassifications had no effect on prior year net income or shareholders’ equity. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendments in this ASU, among other things, require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. The FASB has issued multiple updates to ASU 2016-13 as codified in Topic 326, including ASUs 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, and 2020-03. These ASUs have provided for various minor technical corrections and improvements to the codification as well as other transition matters. Smaller reporting companies who file with the SEC and all other entities who do not file with the SEC are required to apply the guidance for fiscal years, and interim periods within those years, beginning after December 15, 2022. As part of the Company’s implementation efforts, we have reconciled and validated historical loan, charge-off and recovery data, determined segmentation of the loan portfolio for application of the current expected credit losses (“CECL”) calculation, determined the key assumptions to be utilized in the calculation, selected lifetime loss reserve calculation methods and established a methodology framework, updated our qualitative factor framework, performed parallel runs of the CECL calculation, and completed the third party model validation review. The ultimate impact of CECL on the allowance for credit losses will depend on the size and composition of the loan portfolio, the portfolio’s credit quality and economic conditions at the time of adoption, as well as any refinements to the CECL model, methodology and key assumptions. At adoption, the Company will record a cumulative effect adjustment to retained earnings for incremental change in the allowance for credit losses. In March 2022, the FASB issued ASU No. 2022-02, “Financial Instruments-Credit Losses (Topic 326), Troubled Debt Restructurings (“TDRs”) and Vintage Disclosures.” ASU 2022-02 addresses areas identified by the FASB as part of its post-implementation review of the credit losses standard (ASU 2016-13) that introduced the CECL model. The amendments eliminate the accounting guidance for troubled debt restructurings by creditors that have adopted the CECL model and enhance the disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. In addition, the amendments require a public business entity to disclose current-period gross write-offs for financing receivables and net investment in leases by year of origination in the vintage disclosures. The amendments in this ASU should be applied prospectively, except for the transition method related to the recognition and measurement of TDRs, where an entity has the option to apply a modified retrospective transition method resulting in a cumulative-effect adjustment to retained earnings in the period of adoption. For entities that have not yet adopted ASU 2016-13 (such as the Company), the effective dates for the provisions of ASU 2022-02 are the same as the effective dates in ASU 2016-13. Early adoption is permitted if an entity has adopted ASU 2016-13; however, the Company does not expect to adopt ASU 2016-13 in advance of the required implementation date. The Company is currently assessing the impact that ASU 2022-02 will have on its consolidated financial statements.

Nature of Business and Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2022

Nature of Business and Summary of Significant Accounting Policies

Nature of Business and Summary of Significant Accounting Policies

Note 1— Nature of Business and Summary of Significant Accounting Policies

Nature of Banking Activities

John Marshall Bancorp, Inc. (the “Company”), headquartered in Reston, Virginia, became the registered bank holding company under the Bank Holding Company Act of 1956 for its wholly-owned subsidiary, John Marshall Bank (the “Bank”), on March 1, 2017. This reorganization was completed through a one-for-one share exchange in which the Bank’s shareholders received one share of voting common stock of the Company in exchange for each share of the Bank’s voting common stock. The Company was formed on April 21, 2016 under the laws of the Commonwealth Virginia. The Bank was formed on April 5, 2005 under the laws of the Commonwealth of Virginia and was chartered as a bank on February 9, 2006, by the Virginia Bureau of Financial Institutions. The Bank is a member of the Federal Reserve System and is subject to the rules and regulations of the Virginia Bureau of Financial Institutions, the Board of Governors of the Federal Reserve System (the “Federal Reserve”) and the Federal Deposit Insurance Corporation (“FDIC”). The Bank opened for business on April 17, 2006 and provides banking services to its customers primarily in the Washington, D.C. metropolitan area.

Basis of Presentation

The accounting and reporting policies of John Marshall Bancorp, Inc. conform to generally accepted accounting principles in the United States of America (“GAAP”) and reflect practices of the banking industry. The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial reporting and with applicable quarterly reporting regulations of the U.S. Securities and Exchange Commission (“SEC”). They do not include all of the information and notes required by GAAP for complete financial statements. As such, these consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto as of and for the year ending December 31, 2021, included in the Company’s Registration Statement on Form 10, as amended, filed with the SEC on April 18, 2022.

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany accounts and transactions between the Company and the Bank have been eliminated. In preparing financial statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses.

In the opinion of management, all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair presentation of the results of operations in these financial statements, have been made. The results of operations for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be expected for any other interim period or for the full year. All amounts and disclosures included in this quarterly report as of December 31, 2021, were derived from the Company’s audited consolidated financial statements. Certain items in the prior period financial statements have been reclassified to conform to the current presentation. These reclassifications had no effect on prior year net income or shareholders’ equity.

Recent Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendments in this ASU, among other things, require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit

deterioration. The FASB has issued multiple updates to ASU 2016-13 as codified in Topic 326, including ASUs 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, and 2020-03. These ASUs have provided for various minor technical corrections and improvements to the codification as well as other transition matters. Smaller reporting companies who file with the SEC and all other entities who do not file with the SEC are required to apply the guidance for fiscal years, and interim periods within those years, beginning after December 15, 2022. As part of the Company’s implementation efforts, we have reconciled and validated historical loan, charge-off and recovery data, determined segmentation of the loan portfolio for application of the current expected credit losses (“CECL”) calculation, determined the key assumptions to be utilized in the calculation, selected lifetime loss reserve calculation methods and established a methodology framework, updated our qualitative factor framework, performed parallel runs of the CECL calculation, and completed the third party model validation review. The ultimate impact of CECL on the allowance for credit losses will depend on the size and composition of the loan portfolio, the portfolio’s credit quality and economic conditions at the time of adoption, as well as any refinements to the CECL model, methodology and key assumptions. At adoption, the Company will record a cumulative effect adjustment to retained earnings for incremental change in the allowance for credit losses.

In March 2022, the FASB issued ASU No. 2022-02, “Financial Instruments-Credit Losses (Topic 326), Troubled Debt Restructurings (“TDRs”) and Vintage Disclosures.” ASU 2022-02 addresses areas identified by the FASB as part of its post-implementation review of the credit losses standard (ASU 2016-13) that introduced the CECL model. The amendments eliminate the accounting guidance for troubled debt restructurings by creditors that have adopted the CECL model and enhance the disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. In addition, the amendments require a public business entity to disclose current-period gross write-offs for financing receivables and net investment in leases by year of origination in the vintage disclosures. The amendments in this ASU should be applied prospectively, except for the transition method related to the recognition and measurement of TDRs, where an entity has the option to apply a modified retrospective transition method resulting in a cumulative-effect adjustment to retained earnings in the period of adoption. For entities that have not yet adopted ASU 2016-13 (such as the Company), the effective dates for the provisions of ASU 2022-02 are the same as the effective dates in ASU 2016-13. Early adoption is permitted if an entity has adopted ASU 2016-13; however, the Company does not expect to adopt ASU 2016-13 in advance of the required implementation date. The Company is currently assessing the impact that ASU 2022-02 will have on its consolidated financial statements.