Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
CALDWELL THOMAS G
   2. Issuer Name and Ticker or Trading Symbol
MIDDLEFIELD BANC CORP [MBCN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President/Chief Executive Offi
(Last)
(First)
(Middle)
15985 EAST HIGH STREET, P. O. BOX 35		 3. Date of Earliest Transaction (Month/Day/Year)
06/22/2018
(Street)

MIDDLEFIELD, OH 44062		 4. If Amendment, Date Original Filed(Month/Day/Year)
06/25/2018		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 06/22/2018   A   1,018 (1) A $ 51.6 1,677 D  
Common Stock 06/22/2018   F   300 D $ 51.6 1,377 D  
Common Stock               13,522 D (2)  
Common Stock               246.13 (3) I custodian for children

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) $ 23             11/10/2009 11/10/2018 Common Stock 1,000   1,000 D  
Stock Option (right to buy) $ 23             11/10/2009 11/10/2018 Common Stock 1,500   1,500 D  
Stock Option (right to buy) $ 17.55             05/09/2012 05/09/2021 Common Stock 2,500   2,500 D  
Conditional Stock Award (4) $ 32.4               (4) 03/01/2019 Common Stock 865   865 D  
Conditional Stock Award (5) $ 38.6992               (5) 07/20/2020 Common Stock 753   753 D  
Conditional Stock Award (6) $ 48.2               (6) 05/22/2021 Common Stock 2,240   2,240 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
CALDWELL THOMAS G
15985 EAST HIGH STREET
P. O. BOX 35
MIDDLEFIELD, OH 44062		   X     President/Chief Executive Offi  

Signatures

 Thomas G. Caldwell by James R. Heslop, II Power of Attorney   06/26/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Shares were acquired under the terms of a Conditional Stock Grant dated June 22, 2015.
(2) Includes shares held jointly with spouse.
(3) Includes shares acquired under MBCN Dividend Reinvestment Plan.
(4) 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 4, 2016.
(5) 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 July 20, 2017.
(6) 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 May 29, 2018.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.