Exhibit 99

15985 East High Street

P. O. Box 35

Middlefield, Ohio 44062    

Phone: (440) 632-1666    FAX: (440) 632-1700    

www.middlefieldbank.bank

Middlefield Banc Corp. Reports 2017 Third Quarter and Nine Month Financial Results

MIDDLEFIELD, OHIO, October 24, 2017 ◆◆◆◆ Middlefield Banc Corp. (NASDAQ: MBCN) today reported financial results for the three and nine months ended September 30, 2017.

2017 Nine Month Financial Highlights (on a year-over-year basis unless noted):

“The continued strength in our operating and financial results are due to the successful integration of the Liberty Bank N.A. merger, organic loan growth of 16.1%, and the continued focus on increasing profitability by controlling costs, managing risk, and diversifying our revenues,” stated Thomas G. Caldwell, President and Chief Executive Officer. “I am pleased we have been able to grow our margin throughout the year by proactively managing our cost of funds and growing our yield, despite rising rates and a highly competitive banking environment. Middlefield’s community-oriented banking values and customer-centric approach is helping differentiate us within our markets. As a result, our pipeline of new loans in both our Northeast and Central Ohio markets remains robust, and we are excited about Middlefield’s long-term growth opportunities within each of these markets.”

Net income for the nine months ended September 30, 2017 was $7.1 million, or $2.37 per diluted share, compared to net income for the nine months ended September 30, 2016 of $4.8 million, or $2.30 per diluted share. Net income for the 2017 third quarter was $2.5 million, or $0.76 per diluted share, compared to net income for the 2016 third quarter of $1.3 million, or $0.60 per diluted share.

Annualized returns on average equity (“ROE”) and average assets (“ROA”) were 8.82% and 0.89%, respectively, for the 2017 nine-month period, compared with 9.07% and 0.85% for the same period last year. ROE and ROA for the 2017 third quarter were 8.12% and 0.90%, respectively, compared with 6.84% and 0.69% for the 2016 third quarter.

Income Statement

Net interest income for the 2017 nine-month period increased 44.6% to $27.5 million, compared to $19.1 million for the same period last year. Year-to-date, the net interest margin was 3.82%, compared to 3.78% for the same period last year. Net interest income for the 2017 third quarter was $9.5 million, compared to $6.4 million for the 2016 third quarter. The net interest margin for the 2017 third quarter was 3.81%, compared to 3.68% for the same period of 2016. The 48.8% increase in net interest income for the 2017 third quarter was largely a result of a 61.7% increase in interest and fees on loans.

For the 2017 nine months, noninterest income increased 28.8% to $3.9 million, compared to $3.1 million for the same period last year. Noninterest income for the 2017 third quarter was up 47.5% to $1.4 million resulting from an increase of gains on the sale of investment securities and loans, partially offset by lower fees on deposit accounts and other income.

Noninterest expense for the 2017 nine-month period increased 33.6% to $21.3 million, compared to $15.9 million for the same period last year. For the 2017 third quarter, noninterest expense increased 28.9% to $7.3 million, compared to $5.7 million for the same period last year. During the 2017 third quarter, noninterest expense had $338,000 of one-time merger costs associated with the Liberty merger, and year-to-date the company had one-time merger related costs of approximately $1.0 million.

“Asset quality remains strong despite the significant increase in assets we have experienced as a result of strong year-over-year organic loan growth and the contribution of Liberty’s loan portfolio. At September 30, 2017, nonperforming assets to total assets declined to 1.17%, from 1.25% for the same period last year,” said Donald L. Stacy, Chief Financial Officer. “Stable economic activity within our local economies, conservative underwriting practices, and proactive risk management are helping improve loan quality. During the 2017 nine-month period, Middlefield has incurred $1.0 million of nonrecurring merger related expenses. We expect a small amount of additional merger related expenses will continue in the fourth quarter, and as we enter 2018, we do not anticipate any additional costs associated with the Liberty merger. As a result, given our current cost structure and outlook, we believe profitability should improve during the 2017 fourth quarter and throughout 2018.”

Balance Sheet

Total assets at September 30, 2017, increased 41.8% to $1.08 billion, from $762.3 million at September 30, 2016. Net loans at September 30, 2017, were $871.7 million, compared to $580.0 million at September 30, 2016. The 50.3% year-over-year increase in total net loans was across all loan categories, and was a result of organic growth and the contribution of the Liberty merger. Specifically, commercial mortgage loans increased 64.1%, residential mortgage loans increased 22.1%, commercial and industrial loans increased 67.3%, real estate construction loans increased 131.2%, and consumer installment loans increased 304.5%.

Total deposits at September 30, 2017 increased 40.4% to $897.7 million from $639.3 million at September 30, 2016. The company continued to proactively manage its cost of funds and control deposit growth. The investment portfolio, which is entirely classified as available for sale, was $98.3 million at September 30, 2017, compared with $123.1 million at September 30, 2016.

Stockholders’ Equity, Dividends and Shares Outstanding

At September 30, 2017, tangible stockholders’ equity was $100.3 million, an increase of 36.4% from $73.6 million at September 30, 2016. On a per share basis, tangible stockholders’ equity was $31.21 at September 30, 2017, compared to $32.70 at September 30, 2016. The 4.6% decline in tangible book value per share, reflects the increase in the number of shares outstanding as a result of the private placement of stock that closed in May 2017. Through the first nine months of 2017, the company paid cash dividends of $0.81 per share. The dividend payout ratio for the 2017 nine-month period was 35.22%, compared to 35.95% for the same period last year.

At September 30, 2017, the company had a Tier 1 leverage ratio of 10.06%, compared to 10.10% at September 30, 2016.

Asset Quality    

The provision for loan losses was $0.3 million for the 2017 third quarter, compared to $0.1 million for the 2016 third quarter. Nonperforming assets at September 30, 2017, were $12.6 million, compared to $9.5 million at September 30, 2016. Net charge-offs for the 2017 third quarter were $33 thousand, or 0.02% of average loans, annualized, compared to $0.1 million, or 0.09% of average loans, annualized for the same 2016 period. Year-to-date net charge-offs were $0.4 million, or 0.06% of average loans, annualized compared to $0.4 million, or 0.09% of average loans, annualized for the same period last year. The allowance for loan losses at September 30, 2017, stood at $6.9 million, or 0.78% of total loans, compared to $6.3 million or 1.08% of total loans at September 30, 2016.

The following table provides a summary of asset quality and reserve coverage ratios.

Asset Quality History

(dollars in thousands)

Middlefield Banc Corp., headquartered in Middlefield, Ohio, is a bank holding company with total assets of $1.08 billion at September 30, 2017. The bank operates 14 full-service banking centers and an LPL Financial^® brokerage office serving Beachwood, Chardon, Cortland, Dublin, Garrettsville, Mantua, Middlefield, Newbury, Orwell, Solon, Sunbury, Twinsburg, and Westerville. The Bank also operates a Loan Production Office in Mentor, Ohio. Additional information is available at www.middlefieldbank.bank.

This press release of Middlefield Banc Corp. and the reports Middlefield Banc Corp. files with the Securities and Exchange Commission often contain “forward-looking statements” relating to present or future trends or factors affecting the banking industry and, specifically, the financial operations, markets and products of Middlefield Banc Corp. These forward-looking statements involve certain risks and uncertainties. There are a number of important factors that could cause Middlefield Banc Corp.’s future results to differ materially from historical performance or projected performance. These factors include, but are not limited to: (1) a significant increase in competitive pressures among financial institutions; (2) changes in the interest rate environment that may reduce interest margins; (3) changes in prepayment speeds, charge-offs and loan loss provisions; (4) less favorable than expected general economic conditions; (5) legislative or regulatory changes that may adversely affect businesses in which Middlefield Banc Corp. is engaged; (6) technological issues which may adversely affect Middlefield Banc Corp.’s financial operations or customers; (7) changes in the securities markets; or (8) risk factors mentioned in the reports and registration statements Middlefield Banc Corp. files with the Securities and Exchange Commission. Middlefield Banc Corp. undertakes no obligation to release revisions to these forward-looking statements or to reflect events or circumstances after the date of this press release.

MIDDLEFIELD BANC CORP.                     

Consolidated Selected Financial Highlights                     

September 30, 2017 and 2016                     

(Dollar amounts in thousands)                     

(unaudited)    

MIDDLEFIELD BANC CORP.                     

Consolidated Selected Financial Highlights                     

September 30, 2017 and 2016 and December 31, 2016