<SEC-DOCUMENT>0001209191-21-037537.txt : 20210603
<SEC-HEADER>0001209191-21-037537.hdr.sgml : 20210603
<ACCEPTANCE-DATETIME>20210603121132
ACCESSION NUMBER:		0001209191-21-037537
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210524
FILED AS OF DATE:		20210603
DATE AS OF CHANGE:		20210603

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Moore Charles O
		CENTRAL INDEX KEY:			0001543854

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36613
		FILM NUMBER:		21991804

	MAIL ADDRESS:	
		STREET 1:		110 RIVERBEND AVE
		CITY:			LEWIS CENTER
		STATE:			OH
		ZIP:			43035

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MIDDLEFIELD BANC CORP
		CENTRAL INDEX KEY:			0000836147
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				341585111
		STATE OF INCORPORATION:			OH

	BUSINESS ADDRESS:	
		STREET 1:		15985 E HIGH ST
		STREET 2:		P O BOX 35
		CITY:			MIDDLEFILED
		STATE:			OH
		ZIP:			44062-9263
		BUSINESS PHONE:		4406321666

	MAIL ADDRESS:	
		STREET 1:		15985 EAST HIGH STREET
		STREET 2:		P O BOX 35
		CITY:			MIDDLEFIELD
		STATE:			OH
		ZIP:			44062-9263
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>doc4a.xml
<DESCRIPTION>FORM 4/A SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2021-05-24</periodOfReport>

    <dateOfOriginalSubmission>2021-05-24</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000836147</issuerCik>
        <issuerName>MIDDLEFIELD BANC CORP</issuerName>
        <issuerTradingSymbol>MBCN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001543854</rptOwnerCik>
            <rptOwnerName>Moore Charles O</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>15985 EAST HIGH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MIDDLEFIELD</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44062</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President, Central Ohio Region</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>301</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.83</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4640.5</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-24</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>59</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.83</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4581.5</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Conditional Stock Award</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.50</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2024-02-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2253</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2253</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Conditional Stock Award</value>
                <footnoteId id="F4"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>26.09</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2023-02-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1895</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1895</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Conditional Stock Award</value>
                <footnoteId id="F5"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.215</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-03-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2274</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2274</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Acquisition represents the vesting of performance shares granted to the reporting person on May 22, 2018, which vested on the third anniversary of their grant date based upon the Company's total shareholder return.</footnote>
        <footnote id="F2">Includes shares acquired under the MBCN Dividend Reinvestment Plan.</footnote>
        <footnote id="F3">Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipient.  Vesting is subject to a time-based or service condition and a performance-based condition.  The details of the vesting conditions may be found in a Form 8-K filing dated February 25, 2021.</footnote>
        <footnote id="F4">Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipient.  Vesting is subject to a time-based or service condition and a performance-based condition.  The details of the vesting conditions may be found in a Form 8-K filing dated February 26, 2020.</footnote>
        <footnote id="F5">Until the award vests, the award confers no right to vote, no right to dividends, and no other shareholder rights to the recipient.  Vesting is subject to a time-based or service condition and a performance-based condition.  The details of the vesting conditions may be found in a Form 8-K filing dated March 5, 2019.</footnote>
    </footnotes>

    <remarks>This filing corrects a filing of May 24, 2021, which did not account for shares withheld for tax liability.</remarks>

    <ownerSignature>
        <signatureName>Charles O. Moore
by James R. Heslop, II
Power of Attorney</signatureName>
        <signatureDate>2021-06-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
