Exhibit 99

15985 East High Street

P. O. Box 35

Middlefield, Ohio 44062

Phone: 440/632-1666    FAX: 440/632-1700    

www.middlefieldbank.bank

PRESS RELEASE

Middlefield Banc Corp. Reports 2018 First Quarter Financial Results

MIDDLEFIELD, OHIO, April 19, 2018 ◆◆◆◆ Middlefield Banc Corp. (NASDAQ: MBCN) today reported financial results for the 2018 first quarter ended March 31, 2018.

2018 First Quarter Financial Highlights Include (on a year-over-year basis unless noted):

“The 2018 first quarter reflects our optimism toward both the near- and long-term outlook of the bank. Throughout the operation there was a high level of activity as we continued investments required to support Middlefield’s impressive growth that has occurred over the past several years,” stated Thomas G. Caldwell, President and Chief Executive Officer. “During the quarter, Middlefield invested in its team as we added seasoned commercial lenders to our Beachwood and Mentor markets. In addition, to achieve continued loan growth, we proactively increased our level of deposits, which grew 11.4% in the first quarter, compared with the same period a year ago.

“We are excited about breaking ground on our fourth branch in Central Ohio, which will be in Powell and is expected to open late summer 2018. As this and other investments begin to produce returns, we expect profitability and overall activity to increase as 2018 progresses.”

Net income for the 2018 first quarter was $2.6 million, or $0.80 per diluted share, compared to net income for the 2017 first quarter of $2.1 million, or $0.78 per diluted share.

Annualized returns on average equity (“ROE”) and average assets (“ROA”) were 8.73% and 0.94%, respectively, for the 2018 first quarter, compared with 8.73% and 0.84% for the same period last year.

Return on average tangible common equity⁽¹⁾ was 10.23% for the 2018 first quarter, compared with 10.49% for the 2017 first quarter.

Income Statement

Net interest income for the 2018 first quarter was $9.9 million, compared to nearly $8.8 million for the 2017 first quarter. The 13.1% increase in net interest income for the 2018 first quarter was primarily a result of a 20.4% increase in interest and fees on loans. The net interest margin for the 2018 first quarter was 3.82%, compared to 3.84% for the same period of 2017.

Noninterest income for the 2018 first quarter was $786,000, compared to $1.5 million for the same period last year. The 48.0% decline in noninterest income was primarily due to a reduction in investment securities gains and lower gains on the sale of loans primarily due to the company’s decision to stop selling student loans.

Noninterest expense for the 2018 first quarter was $7.3 million, an increase of approximately $78,000 from the 2017 first quarter. The one-time bonus payment made to all employees during the 2018 first quarter impacted noninterest expense by $190,000. Noninterest expense for the 2017 first quarter included $387,000 of additional operating expenses as a result of the Liberty acquisition that did not repeat in the 2018 first quarter.

“Asset quality remains strong despite the significant increase in assets resulting from year-over-year organic loan growth,” said Donald L. Stacy, Chief Financial Officer. “Over the past 12 months, we added nearly $96.7 million of new deposits, which, combined with higher rates on deposits, increased our deposit interest expense by $515,000. Loans to deposits was 98.7% at March 31, 2018 and March 31, 2017, respectively, and 105.1% at December 31, 2017. In addition, profitability during the 2018 first quarter was impacted by our decision to end our student loan program due to our former partner changing the structure of the program, which we believe increased our risk. As a result, gains on the sale of loans declined $230,000. Our net interest margin declined to 3.82% from 3.84% last year as a result of our cost of funds slightly outpacing the increase in the yield on earning assets. Nonperforming loans increased to $17.8 million, primarily due to one loan now classified as a troubled debt. We believe operating leverage will improve during 2018 as the investments made over the past three months start to produce returns.”

Balance Sheet

Total assets at March 31, 2018, increased 3.5% to $1.1 billion, compared to March 31, 2017. Net loans at March 31, 2018, increased 11.4% to $924.8 million, compared to $830.4 million at March 31, 2017. The year-over-year improvement in net loans was primarily a result of a 13.6% increase in commercial mortgage loans, a 5.4% increase in residential mortgage loans, an 8.8% increase in commercial and industrial loans, a 66.5% increase in real estate construction loans, partially offset by an 11.1% decline in consumer installment loans.

Total deposits at March 31, 2018, was $944.6 million, compared to $847.9 million at March 31, 2017. The 11.4% increase in deposits was a result of higher noninterest-bearing demand, savings, and time deposits, offset by lower money market deposits. During the first quarter, the company proactively grew deposits to reduce borrowings and support continued loan growth. The investment portfolio, classified as available for sale, was $91.3 million at March 31, 2018, compared with $110.5 million at March 31, 2017.

Stockholders’ Equity and Dividends

At the end of the 2018 first quarter, shareholders’ equity increased 21% to $120.2 million compared to $99.3 million at March 31, 2017. On a per share basis, shareholders’ equity at March 31, 2018, was $37.28 compared to $35.42 at the same period last year. Tangible stockholders’ equity⁽¹⁾ increased 27.0% to $102.4 million for the 2018 first quarter, compared to $80.6 million at March 31, 2017. On a per-share basis, tangible stockholders’ equity⁽¹⁾ was $31.78 at March 31, 2018, compared to $28.76 at March 31, 2017.

During the 2018 first quarter, the company paid cash dividends of $0.33 per share, which included a special one-time payment of $0.05 per share. This total dividend represented a payout ratio of 40.8%.

At March 31, 2018, the company had an equity to assets leverage ratio of 10.86%, compared to 9.29% at March 31, 2017.

Asset Quality

The provision for loan losses was $210,000 for the 2018 first quarter, compared to $165,000 for the same period a year ago. Nonperforming assets at March 31, 2018, were $18.0 million, compared to $13.7 million at March 31, 2017. The Company reported net recoveries of $151,000, or 0.06% of average loans, annualized during the 2018 first quarter, compared to net charge offs of $43,000, or 0.02% of average loans, annualized at March 31, 2017. The allowance for loan losses at March 31, 2018, stood at $7.6 million, or 0.81% of total loans, compared to $6.7 million or 0.80% of total loans at March 31, 2017.

Middlefield Banc Corp., headquartered in Middlefield, Ohio, is a bank holding company with total assets of $1.1 billion at March 31, 2018. 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

(Dollar amounts in thousands)

(2018 unaudited)

MIDDLEFIELD BANC CORP.

Consolidated Selected Financial Highlights

(Dollar amounts in thousands)

(2018 unaudited)

MIDDLEFIELD BANC CORP.

Consolidated Selected Financial Highlights

(Dollar amounts in thousands, except per share amount)