Note 10 - Proposed Acquisition of Liberty Bancshares	9 Months Ended
Sep. 30, 2022
Notes to Financial Statements
Business Combination Disclosure [Text Block]	NOTE 10 – PROPOSED ACQUISITION OF LIBERTY BANCSHARES On May 26, 2022, Middlefield Banc Corp. (the “Company”), Liberty Bancshares, Inc. (“Liberty”), and MBCN Merger Subsidiary, LLC, a wholly-owned subsidiary of the Company (“Merger Sub”), entered into an Agreement and Plan of Merger (the “Merger Agreement”), pursuant to which Liberty will merge with and into Merger Sub (the “Merger”), with Merger Sub as the surviving entity in the Merger. Promptly following the consummation of the Merger, it is expected that Merger Sub will be dissolved and liquidated and Liberty National Bank (“Liberty Bank”), the banking subsidiary of Liberty, will merge with and into The Middlefield Banking Company (“Middlefield Bank”), the banking subsidiary of the Company (the “Bank Merger”). Middlefield Bank will be the surviving bank in the Bank Merger (the “Surviving Bank”). Under the terms and subject to the conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of the voting common stock, $1.25 par value per share, and each share of non-voting common stock, no par value, of Liberty (the “Liberty Common Stock”) issued and outstanding immediately prior to the Effective Time, will be converted, in accordance with the procedures set forth in the Merger Agreement, into the right to receive, without interest, 2.752 shares (the “Exchange Ratio” and such shares, the “Merger Consideration”) of the common stock, no par value per share, of the Company (the “Company Common Stock”). The Merger Agreement provides that an outstanding and unexercised warrant issued to Castle Creek Partners VI, LP (“Castle Creek”) to purchase shares of Liberty convertible perpetual preferred stock, Series A, shall be canceled and converted into the right to receive the Merger Consideration.

Note 10 - Proposed Acquisition of Liberty Bancshares

9 Months Ended

Sep. 30, 2022

Business Combination Disclosure [Text Block]

NOTE 10 – PROPOSED ACQUISITION OF LIBERTY BANCSHARES

On May 26, 2022, Middlefield Banc Corp. (the “Company”), Liberty Bancshares, Inc. (“Liberty”), and MBCN Merger Subsidiary, LLC, a wholly-owned subsidiary of the Company (“Merger Sub”), entered into an Agreement and Plan of Merger (the “Merger Agreement”), pursuant to which Liberty will merge with and into Merger Sub (the “Merger”), with Merger Sub as the surviving entity in the Merger. Promptly following the consummation of the Merger, it is expected that Merger Sub will be dissolved and liquidated and Liberty National Bank (“Liberty Bank”), the banking subsidiary of Liberty, will merge with and into The Middlefield Banking Company (“Middlefield Bank”), the banking subsidiary of the Company (the “Bank Merger”). Middlefield Bank will be the surviving bank in the Bank Merger (the “Surviving Bank”).

Under the terms and subject to the conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), each share of the voting common stock, $1.25 par value per share, and each share of non-voting common stock, no par value, of Liberty (the “Liberty Common Stock”) issued and outstanding immediately prior to the Effective Time, will be converted, in accordance with the procedures set forth in the Merger Agreement, into the right to receive, without interest, 2.752 shares (the “Exchange Ratio” and such shares, the “Merger Consideration”) of the common stock, no par value per share, of the Company (the “Company Common Stock”). The Merger Agreement provides that an outstanding and unexercised warrant issued to Castle Creek Partners VI, LP (“Castle Creek”) to purchase shares of Liberty convertible perpetual preferred stock, Series A, shall be canceled and converted into the right to receive the Merger Consideration.