Exhibit 99.1

Civista Bancshares, Inc. Announces Continued Strong Earnings in Third Quarter 2015

Sandusky, Ohio, October 23, 2015 – Civista Bancshares, Inc. (NASDAQ:CIVB) PRNewswire (“Civista”) reported net income attributable to common shares of $2.9 million, or $0.30 per diluted share, for the third quarter of 2015, compared with $1.9 million, or $0.21 per diluted share, for the prior year period. For the nine-month period ended September 30, 2015, Civista reported net income available to common shareholders of $8.4 million or $0.87 per diluted share, compared to $5.8 million, or $0.64 per diluted share, in the same period of 2014.

“Through the first nine months of 2015 we have increased our diluted earnings per share by 36% compared to the first nine months of 2014. We completed the acquisition of TCNB Financial Corp (“TCNB”) in the first quarter of the year. We have decreased our nonperforming assets 25%, increased our net interest income and kept our noninterest income and noninterest expense stable.” said James O. Miller, Chairman, President and CEO of Civista.

Results of Operations:

Net interest income for the third quarter of 2015 increased $1.7 million, or 16.1% and increased $4.1 million, or 13.2%, for the nine months ended September 30 compared to the same periods of 2014. Tax equivalent net interest margin was 4.13% for the third quarter and 3.91% for the nine months ended September 30, 2015. The increase in net interest income for the quarter and nine months ended September 30, 2015 was due both to an increase in average loans outstanding as well as a decrease in cost of funds. Additionally during the third quarter, interest income was increased by $281 thousand due to the payoff of a loan that had been on nonaccrual status for significant period of time. Mr. Miller continued, “As we have discussed in previous quarters, our net interest margin is seasonally affected by an influx of cash in the first quarter for the tax refund processing program. Our core net interest margin has remained near 4.00%. This is an accomplishment I am proud of given the existing long-term low interest rate environment.”

The provision for loan losses was $400 thousand and $0 for the third quarter of 2015 and 2014, respectively. The provision for loan losses was $1.2 million and $1.5 million for the nine months ended September 30, 2015 and 2014, respectively. The decrease in provision for loan losses for the nine months of 2015 is primarily related to improved asset quality.

During the quarter, noninterest income totaled $3.1 million, an increase of $64 thousand, or 2.1%, compared to the prior year’s third quarter. Year-to-date noninterest income increased $116 thousand, or 1.1%, when compared to the first nine months of 2014.

Service charge income increased in both the three and nine-month periods, primarily due to an increase in business service charges, as well as service charge fees instituted in our Dayton market since the acquisition of TCNB. Gain on sale of loans increased $30 thousand and $418 thousand in the three and nine-month periods, respectively due to additional volume of loans sold as well as an increase in the premium on loans sold. Trust fees decreased $163 thousand and $237 thousand for the three and nine-month periods, respectively, due to a decrease in trust assets Tax refund processing fees were down $321 thousand, or 13.8% when compared to the nine months of 2014, due to a change in the fee structure for 2015.

Mr. Miller continued, “While the mix of our noninterest income has changed, the overall number has continued to increase. Market declines in the third quarter contributed to a decrease in trust fees, which is the only category that was down for the quarter.”

Noninterest expense totaled $10.7 million for the three months ended September 30, 2015 and 2014. Year-to-date noninterest expense increased $1.1 million, or 3.7%, when compared to the nine months of 2014.

Salaries, wages and benefits expense increased $371 thousand for the third quarter and $1,071 thousand for the nine-month period ending September 30, 2015. The increase in salaries, wages and benefits expense was due to normal merit increases, the addition of TCNB employees, as well as a change to our 401k match expense. On January 1, 2015, the 401k plan was modified to a safe harbor plan which led to an increase in the company match. Contracted data processing and professional fees increased for the nine-month period ended September 30, 2015. These increases were primarily due to expenses related to the acquisition of TCNB. Overall acquisition related expenses included in the nine months ended September 30, 2015 approximate $374 thousand.

Mr. Miller continued, “While we have added three offices from the acquisition of TCNB, we have been able to keep our expenses flat for the third quarter. Removing the acquisition related expenses for the nine-month period, our noninterest expenses only increased 2.4%.”

Balance Sheet

Total assets increased $100.1 million, or 8.3%, from December 31, 2014 to September 30, 2015. This was due primarily to the acquisition of TCNB, which closed on March 6, 2015. Total assets of TCNB prior to the merger were $97.4 million, including $76.8 million in loans.

Total Loans increased $85.4 million or 9.3% from December 31, 2014 to September 30, 2015. The increase in total loans is primarily due to the acquisition of TCNB which added $76.8 million in loans.

Total deposits increased $87.0 million, or 9.0%, from December 31, 2014 to September 30, 2015. The increase in deposits was primarily due to the acquisition of TCNB, which included $86.9 million in deposits.

Total shareholder’s equity increased $7.4 million, or 6.4%, from December 31, 2014 to September 30, 2015 due to increased retained earnings of $7.2 million and an increase in Accumulated Other Comprehensive Income of $195 thousand.

Asset Quality

Nonperforming assets at September 30, 2015 were $14.3 million, a $4.7 million decrease from December 31, 2014, and a $6.6 million decrease compared to September 30, 2014.

Mr. Miller continued, “During the recession we worked with many of our customers to keep them in their homes and businesses. As we move further from the recession we see continued improvements in asset quality. Our non-performing assets have decreased 31% since September 2014 and 25% since December 31, 2014. At the same time we have seen increases in net interest income and stability in non-interest income and expense. We are optimistic about the prospects for maintaining our momentum for the remainder of 2015.”

Civista Bancshares, Inc. is a $1.3 billion financial holding company headquartered in Sandusky, Ohio. The Company’s banking subsidiary, Civista Bank, operates 28 locations in North Central, West Central and Southwestern Ohio.

Civista Bancshares, Inc. may be accessed at www.civb.com. The Company’s common shares are traded on the NASDAQ Capital Market under the symbol “CIVB”. The Company’s depositary shares, each representing a 1/40^th ownership interest in a Series B Preferred Share, are traded on the NASDAQ Capital Market under the symbol “CIVBP”.

This press release may contain forward-looking statements regarding the financial performance, business prospects, growth and operating strategies of Civista. For these statements, Civista claims the protections of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Statements in this press release should be considered in conjunction with the other information available about Civista, including the information in the filings we make with the Securities and Exchange Commission. Forward-looking statements provide current expectations or forecasts of future events and are not guarantees of future performance. The forward-looking statements are based on management’s expectations and are subject to a number of risks and uncertainties. We have tried, wherever possible, to identify such statements by using words such as “anticipate,” “estimate,” “project,” “intend,” “plan,” “believe,” “will” and similar expressions in connection with any discussion of future operating or financial performance. Although management believes that the expectations reflected in such forward-looking statements are reasonable, actual results may differ materially from those expressed or implied in such statements. Risks and uncertainties that could cause actual results to differ materially include risk factors relating to the banking industry and the other factors detailed from time to time in Civista’ reports filed with the Securities and Exchange Commission, including those described in “Item 1A Risk Factors” of Part I of Civista’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014. Undue reliance should not be placed on the forward-looking statements, which speak only as of the date hereof. Civista does not undertake, and specifically disclaims any obligation, to publicly release the result of any revisions that may be made to update any forward-looking statement to reflect the events or circumstances after the date on which the forward-looking statement is made, or reflect the occurrence of unanticipated events, except to the extent required by law.

For additional information, contact:

James O. Miller

Chairman, President and CEO

Civista Bancshares, Inc.

888-645-4121

Civista Bancshares Inc.

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