Exhibit 99.1

FOR IMMEDIATE RELEASE

CONTACT

Kristine D. Brenner

Director of Investor Relations

(810) 257-2506

kristine.brenner@citizensbanking.com

Citizens Republic Bancorp Reports Fourth Quarter Earnings

FLINT, MICHIGAN, January 22, 2013—Citizens Republic Bancorp, Inc. (Nasdaq: CRBC) announced net income attributable to common shareholders of $17.0 million or $0.42 per diluted share for the three months ended December 31, 2012, compared to $14.9 million or $0.37 per diluted share for last quarter, and $12.3 million or $0.31 per diluted share for the fourth quarter of last year. For the year ended December 31, 2012, Citizens recorded net income attributable to common shareholders of $347.9 million or $8.61 per share compared to a net loss of $16.3 million or $0.41 per share for the prior year. Year to date 2012 results include a $275.5 million or $6.82 per share tax benefit related to the elimination of the valuation allowance against the deferred tax asset in the second quarter.

“We are pleased with our 2012 earnings results, which reflect our bankers’ persistent execution of our strategic initiatives. Our success during 2012 allowed us to complete our key priorities including terminating our written regulatory agreement and restoring our deferred tax asset. In addition, we are in the midst of paying our accrued trust preferred dividends and our TARP obligation will be repaid through our pending merger with FirstMerit. We are proud of the hard work and dedication of everyone at Citizens as together we have addressed the many challenges from the last several years, and have emerged as a stronger banking franchise,” commented Cathleen Nash, president and chief executive officer.

“While we continue to execute on our priorities, we are also looking ahead to our combination with FirstMerit as we create a premier Midwest banking franchise providing enhanced products and services to our clients and significant long-term value to our shareholders,” added Nash.

Balance Sheet

Citizens continues to enjoy a strong core deposit funding base. Core deposits of $5.4 billion at December 31, 2012 decreased slightly from the third quarter as a result of an expected seasonal reduction in public funds balances, but increased $255.8 million, or 4.9% from December 31, 2011. Time deposits decreased $69.5 million, or 3.9%, from the third quarter and $490.0 million, or 22.3%, from the fourth quarter of 2011 due to the intentional non-renewal of high cost rate sensitive retail and brokered balances.

Total assets decreased $138.1 million from the third quarter as a reduction in loan portfolio balances was partially offset by an increase in investment securities balances. Over the past year, growth within the C&I and indirect consumer portfolios helped to partially mitigate balance reductions in the commercial real estate, residential mortgage, and direct consumer portfolios. Citizens continues to emphasize C&I and consumer lending as key components of its strategic plan.

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Capital

Citizens continues to grow capital organically through earnings and maintains a strong capital position.

Capital Ratios

Net Interest Income and Margin

Net interest margin was 3.50% in the fourth quarter, a seven basis point decrease from last quarter and a twelve basis point decrease from the fourth quarter of last year. The decreases were driven by the continued low interest rate environment, which has resulted in reduced yields on our earning assets. The negative effects on asset yields were partially offset by a more advantageous funding mix and reduced funding costs. In the fourth quarter the negative pressures were also somewhat offset by an increase in commercial loan fees collected with the restructuring of several larger client relationships. For the year ended December 31, 2012, net interest margin decreased two basis points over the prior year to 3.56%.

Net interest income for the fourth quarter was $73.2 million, a reduction of $2.6 million from last quarter and a decrease of $4.9 million from the fourth quarter of last year. The decreases from both periods are result of both lower average earning assets and margin compression. For the year ended December 31, 2012, net interest income decreased $12.3 million compared to 2011 primarily due to a reduction in average earning assets.

Credit Quality

Credit quality continued its strong performance.

Noninterest Income and Expense

Total noninterest income was $22.0 million, a reduction of $1.7 million from the third quarter and a reduction of $2.3 million from the fourth quarter of last year. For the full year, noninterest income was $92.3 million; a decrease of $2.9 million compared to 2011.

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Noninterest expense was $6.9 million less than last quarter and $1.5 million lower than the fourth quarter of last year.

For the year ended December 31, 2012, noninterest expense decreased $12.5 million or 4% from 2011 as lower credit related expenses were partially offset by higher salaries and employee benefits and merger-related expenses.

Income Taxes and Deferred Tax Asset

The income tax benefit for 2012 totaled $273.0 million, compared with a benefit of $20.3 million for 2011. The majority of the tax benefit in 2012 was recorded in the second quarter as the result of eliminating the valuation allowance against our deferred tax asset.

Conference Call

Citizens’ senior management will review the quarter’s results in a conference call at 12:00 p.m. Eastern Time on Tuesday, January 22, 2013. A live audio webcast is available on Citizens’ investor relations page at www.citizensbanking.com or by calling (866) 952-1906 (conference ID: Citizens Republic). To listen to the conference call, please connect approximately 10 minutes prior to the scheduled conference time. A recording will be available approximately two hours after the completion of the conference call at www.citizensbanking.com, where it will be archived for 90 days.

Use of Non-GAAP Financial Measures

In addition to results presented in accordance with generally accepted accounting principles (“GAAP”), this release includes non-GAAP financial measures such as tangible equity to tangible assets ratio, tangible common equity to tangible assets ratio, Tier 1 common equity ratio, pre-tax pre-provision profit, net interest margin, the efficiency ratio, and adjusted earnings per share. Citizens believes these non-GAAP financial measures provide additional information that is useful to investors in understanding the underlying performance of Citizens, its business and performance trends, and such measures help facilitate performance comparisons with others in the banking industry. Non-GAAP financial measures have inherent limitations, are not required to be uniformly applied and are not audited. Readers should be aware of these limitations and should be cautious as to their use of such measures. To mitigate these limitations, Citizens has procedures in place to ensure that these measures are calculated using the appropriate GAAP or regulatory components in their entirety to ensure that Citizens’ performance is properly reflected to facilitate consistent period-to-period comparisons. Although Citizens believes the above non-GAAP financial measures disclosed in this release enhance investors’ understanding of its business and performance, these non-GAAP measures should not be considered in isolation, or as a substitute for GAAP basis financial measures. See our related Form 8-K for further discussion regarding these non-GAAP financial measures.

Corporate Profile

Citizens Republic Bancorp, Inc. is a diversified financial services company providing a wide range of commercial, consumer, mortgage banking, trust and financial planning services to a broad client base. Citizens serves communities in Michigan, Ohio, and Wisconsin with 219 offices and 248 ATMs. Citizens is the largest bank holding company headquartered in Michigan with roots dating back to 1871 and is the 58^th largest bank holding company headquartered in the United States. More information about Citizens is available at www.citizensbanking.com.

Safe Harbor Statement

Discussions and statements in this release that are not statements of historical fact, including without limitation, statements that include terms such as “will,” “may,” “should,” “believe,” “expect,” “anticipate,” “estimate,” “project,” “intend,” and “plan,” and statements regarding Citizens’ future financial and operating results, plans, objectives, expectations and intentions, are forward-looking statements that involve risks and uncertainties, many of which are beyond Citizens’ control or are subject to change. No forward-looking statement is a guarantee of future performance and actual results could differ materially.

Factors that could cause or contribute to actual results differing materially from Citizens’ expectations include the risks and uncertainties detailed from time to time in Citizens’ annual and quarterly filings with

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the SEC, which are available at the SEC’s website www.sec.gov. Other factors not currently anticipated may also materially and adversely affect Citizens’ results of operations, cash flows, financial position and prospects. There can be no assurance that future results will meet expectations. While Citizens believes that the forward-looking statements in this release are reasonable, you should not place undue reliance on any forward-looking statement. In addition, these statements speak only as of the date made. Citizens does not undertake, and expressly disclaims, any obligation to update or alter any statements, whether as a result of new information, future events or otherwise, except as required by applicable law.

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Consolidated Balance Sheets (Unaudited)

Citizens Republic Bancorp, Inc.

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Consolidated Statements of Operations (Unaudited)

Citizens Republic Bancorp, Inc.

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Selected Quarterly Information (Unaudited)

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Loan Portfolios

Delinquency Rates By Loan Portfolio