Exhibit 99.1

Mercantile Bank Corporation Reports Second Quarter 2012 Results

Full repurchase of TARP preferred stock, improved asset quality, increased profitability and growth of loan portfolio

GRAND RAPIDS, Mich., July 17, 2012 – Mercantile Bank Corporation (NASDAQ: MBWM) (“Mercantile”) reported net income attributable to common shares of $3.3 million, or $0.36 per diluted share, for the second quarter of 2012, compared with net income attributable to common shares of $2.4 million, or $0.27 per diluted share, for the prior-year period. On a pre-tax basis, income was $5.8 million in the second quarter of 2012 compared to $2.7 million in the prior-year second quarter, an increase of 115 percent.

The second quarter was highlighted by:

“The second quarter marked a number of significant accomplishments that has Mercantile poised to take advantage of lending and market opportunities,” said Michael Price, Chairman and CEO of Mercantile Bank Corporation. “Our improving levels of profitability and the strength of our balance sheet enabled us to complete the repurchase of the preferred stock outstanding under TARP. For the first time in the Company’s history, we had a net recovery of loan losses and recorded a negative provision for loan losses, reflecting an especially dynamic quarter pertaining to asset quality improvement. Our performance in the second quarter highlights the strength of our community banking model and the value we bring to the communities we serve.”

Operating Results

Total revenue, which consists of net interest income and noninterest income, was $13.5 million during the 2012 second quarter, down $1.4 million or about 9 percent from the $14.9 million generated during the second quarter of 2011, primarily reflecting a reduction in earning assets. Net interest income was $11.5 million, down $1.7 million or 12.5 percent from the $13.2 million earned in the prior-year second quarter. The decrease in net interest income resulted from a 13.0 percent decline in average earning assets as part of management’s strategic initiative to reduce commercial real estate exposure and shift certain loans out of the loan portfolio. The net interest margin during the second quarter of 2012 was 3.63 percent, slightly higher than the level during the second quarter of 2011 and remaining well above the historical average level.

Noninterest income for the 2012 second quarter was $2.0 million, up $0.2 million or 13.9 percent from the comparable 2011 period. The increase in noninterest income primarily resulted from increased residential mortgage banking fee income and an increase in rental income on foreclosed properties.

Mercantile had a negative $3.0 million provision for loan losses during the second quarter of 2012 compared to a provision expense of $1.7 million for the year-ago quarter. The negative provision expense is the result of several factors, including: a net recovery of prior-period loan charge-offs of $1.7 million, certain specific reserve allocations that were fully eliminated or significantly reduced due to successful collection efforts, a low level of loan-rating downgrades, and a significant number of loan-rating upgrades.

Noninterest expense for the 2012 second quarter was $10.6 million, up $0.2 million from the same period in 2011. Salaries and benefits totaled $4.9 million, up $0.5 million from the prior-year quarter, primarily reflecting the expense associated with certain employee benefit programs that had been suspended or lowered in prior years. Costs associated with the administration and resolution of problem assets, including legal expenses, property tax payments, appraisal costs and write-downs on foreclosed properties, totaled $2.1 million during the 2012 second quarter, up $0.1 million from the year-ago quarter. Federal Deposit Insurance Corporation insurance premiums were $0.3 million in the second quarter of 2012, down $0.4 million from the 2011 second quarter, primarily resulting from a decreased assessment rate that reflects the Company’s improved financial condition and operating performance.

“Once again, we saw the benefit of our disciplined approach to managing our loan portfolio with a focus on appropriate underwriting and administration,” added Price. “This effort has had a substantial positive impact on our operating performance and the strength of our financial condition, and has enabled us to repurchase all of our outstanding preferred stock without issuing additional stock or debt.”

Balance Sheet

Over the past several years, Mercantile has focused on reducing its exposure to loans secured by commercial real estate. While efforts to reduce certain segments of the commercial real estate portfolio continue, total loans increased $9.3 million during the second quarter of 2012 as improved economic conditions and continued relationship building efforts have led to increased lending opportunities. As of June 30, 2012, total assets were $1.39 billion, down $48.0 million or 3.3 percent from December 31, 2011; total loans decreased $11.4 million, or 1.1 percent, to $1.06 billion over the same period. Compared to June 30, 2011, total assets declined $153 million, or 9.9 percent, and total loans declined $62.0 million, or 5.5 percent.

Real estate loans comprise a majority of Mercantile’s loan portfolio. At June 30, 2012, real estate loans, excluding residential mortgage loans representing permanent financing of owner-occupied dwellings and home equity lines of credit, were $706 million or approximately 67 percent of total loans, representing a decline of $65.9 million, or 8.5 percent, from $772 million, or 68.8 percent of total loans, at June 30, 2011.

Non-owner-occupied commercial real estate (“CRE”) loans totaled $351 million as of June 30, 2012 (33.1 percent of total loans), a decline of $78.9 million over the past 12 months. Owner-occupied CRE loans were $282 million at the end of the second quarter of 2012, an increase of $16.7 million from a year ago. Vacant land, land development and construction (“C&D”) loans, including both residential and commercial projects, totaled $73.9 million at June 30, 2012, down $3.6 million from a year ago. The commercial and industrial (“C&I”) segment of the loan portfolio was $277 million at June 30, 2012, an increase of $10.9 million since year-end 2011 and an increase of $15.3 million over the past 12 months. The average balance of commercial lines of credit has remained relatively stable since early 2011 after declining for several years.

LOANS SECURED BY REAL ESTATE

Note — Excludes residential mortgage loans representing permanent financing of owner-occupied dwellings and home equity lines of credit.

Since December 2008, Mercantile has been focused on improving liquidity by reducing wholesale funding and growing local deposits, especially interest-bearing checking and money market deposit accounts. As of June 30, 2012, total deposits were $1.11 billion, a decline of $494 million since year-end 2008. By comparison, local deposits increased $327 million to $797 million since year-end 2008, representing 72.1 percent of total deposits compared to 29.4 percent at December 31, 2008. Approximately 77 percent, or $252 million, of local deposit growth since year-end 2008 occurred in the interest-bearing checking and money market deposit account categories, while DDA checking accounted for $53.8 million, or about 17 percent of total growth. Growth in local deposits was driven primarily by the introduction of innovative new products, various deposit-gathering initiatives, enhanced advertising and branding campaigns, and transfers from maturing time deposit accounts.

Wholesale funds were $343 million, or 28.8 percent of total funds, as of June 30, 2012, compared to $1.41 billion, or 71.5 percent of total funds, as of December 31, 2008. Compared to a year ago, wholesale funding was reduced by $180 million, or 34.3 percent. The $1.07 billion decline in wholesale funding since the end of 2008 reflects both the shift toward local deposits, as well as a $796 million decline in total loans. This strategy has allowed Mercantile to reduce brokered deposits and Federal Home Loan Bank advances as they matured since year-end 2008.

Short-term investments, consisting of federal funds sold and interest-bearing bank deposits, averaged $71.4 million during the second quarter of 2012. In addition to its short-term investments, at the end of the second quarter of 2012, Mercantile had approximately $140 million of borrowing capacity through various established lines of credit to meet potential funding needs, as well as $33.2 million of U.S. Government securities available to sell.

Asset Quality

Nonperforming assets (“NPAs”) at June 30, 2012 were $40.1 million, or 2.9 percent of total assets, compared to $60.4 million as of December 31, 2011, and $61.9 million as of June 30, 2011 (4.2 percent and 4.0 percent of total assets, respectively). This represents a decline of $20.3 million or 33.6 percent from the end of 2011, and a decline of $21.8 million or 35.3 percent from the year-ago quarter-end.

Robert B. Kaminski, Jr., Mercantile’s Executive Vice President and Chief Operating Officer, noted: “We made outstanding progress in improving our asset quality during the second quarter, as evidenced by the decrease in nonperforming assets. The ratio of nonperforming assets to total assets decreased to less than 3 percent compared with levels greater than 4 percent at the end of 2011, driven by loan upgrades and declines in nonperforming loans. As we build on the improvement in asset quality, we expect to continue leveraging the key strategic benefits of being a community bank. Even though

business owners have been cautious in expanding, as we highlight the value of our strategic relationship approach and close proximity to their businesses, we expect to capture additional market share as growth opportunities arise.”

Nonperforming loans (“NPLs”) totaled $28.5 million as of June 30, 2012, down $10.1 million and $14.9 million, respectively, from the linked quarter-end and the year-ago quarter-end, while foreclosed real estate and repossessed assets declined $2.0 million and $6.9 million, respectively, from the linked and year-ago quarter-ends. CRE loans represented 62.5 percent of NPLs, or $17.8 million at June 30, 2012. Investor-owned nonperforming CRE loans accounted for $13.2 million of total CRE nonperforming loans (3.8 percent of $351 million investor-owned CRE loans), while owner-occupied CRE nonperforming loans accounted for $4.6 million (1.6 percent of $282 million owner-occupied CRE loans).

Nonperforming C&D loans were $3.4 million as of June 30, 2012, a decrease of $0.1 million since the year-ago quarter-end. Nonperforming C&I loans were $1.8 million as of June 30, 2012, a decline of $2.0 million since June 30, 2011. Owner-occupied and rental residential NPLs were $5.5 million as of June 30, 2012, down $3.1 million since the year-ago quarter-end.

NONPERFORMING ASSETS

During the second quarter of 2012, Mercantile added $3.3 million of NPAs to its problem asset portfolio and successfully disposed of $13.0 million through a combination of asset sales and principal pay-downs. Loan charge-offs were $1.3 million and foreclosed asset valuation write-downs were $1.1 million. In total, NPAs decreased by a net $12.1 million during the second quarter of 2012.

Improvement in asset quality is also apparent on a full-year basis. During the 12-month period ended June 30, 2012, Mercantile added $26.9 million of problem assets to its NPA portfolio, successfully disposed of $41.4 million, and charged off or wrote down an additional $7.3 million. In total, NPAs declined by a net $21.8 million since June 30, 2011.

NONPERFORMING ASSETS RECONCILIATION

Net loan recoveries were $1.7 million during the second quarter of 2012, or an annualized negative 0.7 percent of average loans, compared with net loan charge-offs of $5.6 million (2.1 percent annualized) and $5.1 million (1.7 percent annualized) for the linked and prior-year quarters, respectively.

NET LOAN CHARGE-OFFS (RECOVERIES)

Capital Position

Shareholders’ equity totaled $150 million as of June 30, 2012, a decrease of $15.3 million from December 31, 2011. During the second quarter of 2012, Mercantile repurchased the entire $21.0 million of preferred stock that was sold to the U.S. Department of the Treasury on May 15, 2009. To fund the repurchase, the Bank paid a cash dividend to the Company in approximately the same amount. The Bank remains “well-capitalized” with a total risk-based capital ratio of 14.6 percent as of June 30, 2012, compared to 15.5 percent at December 31, 2011. At June 30, 2012, the Bank had approximately $54.4 million in excess of the 10.0 percent minimum regulatory threshold required to be considered a “well-capitalized” institution. Mercantile reported 8,610,850 total shares outstanding at June 30, 2012.

On July 3, 2012 Mercantile repurchased, for $7.5 million, the warrant it sold to the U.S. Department of the Treasury on May 15, 2009. The warrant provided for the purchase of 616,438 shares of Mercantile common stock at a price of $5.11 per share. To fund the repurchase, the Bank paid a cash dividend to the Company in approximately the same amount. On a pro-forma basis, assuming the warrant repurchase and the payment of the cash dividend had been consummated on June 30, 2012, Mercantile’s and the Bank’s capital ratios would decline by about 55 to 65 basis points.

Mr. Price concluded: “We are very pleased with the strong performance we’ve posted so far in 2012. Our earnings performance and financial condition continued to improve, which combined with achieving additional important milestones provides us greater flexibility to take advantage of lending and market opportunities as they arise. We were able to fully repurchase the preferred stock and the warrant from the Treasury over the past several months without having to access the capital markets or issue debt, and still maintain a strong regulatory capital position. We remain dedicated to the key strategies that have enabled us to resume the path of disciplined growth for long-term performance.”

About Mercantile Bank Corporation

Based in Grand Rapids, Michigan, Mercantile Bank Corporation is the bank holding company for Mercantile Bank of Michigan. Founded in 1997 to provide banking services to businesses, individuals and governmental units, the Bank differentiates itself on the basis of service quality and the expertise of its banking staff. Mercantile has seven full-service banking offices in Grand Rapids, Holland and Lansing, Michigan. Mercantile Bank Corporation’s common stock is listed on the NASDAQ Global Select Market under the symbol “MBWM.”

Forward-Looking Statements

This news release contains comments or information that constitute forward-looking statements (within the meaning of the Private Securities Litigation Reform Act of 1995) that are based on current expectations that involve a number of risks and uncertainties. Actual results may differ materially from the results expressed in forward-looking statements. Factors that might cause such a difference include changes in interest rates and interest rate relationships; demand for products and services; the degree of competition by traditional and nontraditional competitors; changes in banking regulation or actions by bank

regulators; changes in tax laws; changes in prices, levies, and assessments; the impact of technological advances; governmental and regulatory policy changes; the outcomes of contingencies; trends in customer behavior as well as their ability to repay loans; changes in local real estate values; changes in the national and local economies; and other factors, including risk factors, disclosed from time to time in filings made by Mercantile with the Securities and Exchange Commission. Mercantile undertakes no obligation to update or clarify forward-looking statements, whether as a result of new information, future events or otherwise.

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Second Quarter 2012 Results

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CONSOLIDATED BALANCE SHEETS

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Second Quarter 2012 Results

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CONSOLIDATED REPORTS OF OPERATIONS

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Second Quarter 2012 Results

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CONSOLIDATED FINANCIAL HIGHLIGHTS

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