Exhibit 99.1

FIRSTBANK CORPORATION ANNOUNCES

FOURTH QUARTER AND FULL YEAR 2013 RESULTS

Alma, Michigan (FBMI) ---- Thomas R. Sullivan, President and Chief Executive Officer of Firstbank Corporation, announced net income of $3,159,000 for the fourth quarter of 2013, increasing 5.4% from $2,998,000 for the fourth quarter of 2012, with net income available to common shareholders of $3,159,000 in the fourth quarter of 2013 increasing 13.5% from $2,783,000 in the fourth quarter of 2012. Diluted earnings per share were $0.39 in the fourth quarter of 2013 compared to $0. 35 in the fourth quarter of 2012. Returns on average assets and average equity for the fourth quarter of 2013 were 0. 85% and 9.2%, respectively, compared to 0.79% and 8.1% respectively in the fourth quarter of 2012.

For full year 2013, net income of $12,234,000 increased 16.1% from $10,534,000 for 2012, with net income available to common shareholders of $11,753,000 in 2013 increasing 26.9% from $9,259,000 in 2012. Diluted earnings per share were $1.45 in 2013 compared to $1.16 in 2012. Returns on average assets and average equity for full year 2013 were 0.82% and 8.7%, respectively, compared to 0.70% and 7.0% respectively in 2012.

Expenses related to the pending merger with Mercantile Bank Corporation in the amount of $133,000 in the fourth quarter of 2013 and $738,000 in the third quarter of 2013 were recorded. These expenses reduced after tax earnings and net income available to common shareholders by $117,000 in the fourth quarter, $569,000 in the third quarter, and $686,000 for the full year. Correspondingly, they reduced diluted earnings per share by $0.01 in the fourth quarter, $0.07 in the third quarter, and $0.08 for the full year.

Mr. Sullivan stated, “Two factors stand out as important in our fourth quarter results. First, we continued to make great progress on reducing non-accrual loans and other real estate owned. Resolving these situations and getting these non-performing assets removed from our balance sheet allow our lending staff to focus more on developing new relationships and serving existing good customers. Second, we have achieved growth in portfolio loans now for three consecutive quarters, which helps our earning asset mix and is a sign of an improving economic environment. The improving asset mix helps to combat more competitive pricing pressure on new and renewed loans and will eventually be the key to maintaining and improving net interest margin.

“We were gratified with the robust approval by the shareholders of both companies, at the special shareholder meetings held during the fourth quarter, of the previously announced merger with Mercantile Bank Corporation. We are now awaiting the completion of the regulatory approval process. Our merger and integration teams, comprised of key members of management from both companies, have completed most of the tasks needed for a merger consummation.

“Strong improvement in our earnings and asset quality metrics, and our exciting plans for the future are the result of much hard work and dedication to our customers and company by our wonderful staff, and we thank them for their efforts.”

Provision for Loan Losses. The provision for loan losses was zero in the fourth quarter of 2013 (and third quarter of 2013), compared to the $1,338,000 amount required in the fourth quarter of 2012. Net charge-offs of $1,609,000 in the fourth quarter of 2013 represented loans that had been provided for previously, and the improving risk measures and strong level of allowance for loan losses made it unnecessary to provide additional amounts to the allowance in the quarter.

Net Interest Income. Net interest income, at $13,042,000 in the fourth quarter of 2013 was 2.3%, lower than in the fourth quarter of 2012, as a result of a 7 basis point lower net interest margin compared to the year-ago quarter. Net interest margin in the fourth quarter of 2013 increased to 3.84% from 3.82% in the third quarter of 2013. Average portfolio loans grew in the fourth quarter of 2013, helping to improve earning asset mix. The yield on average earning assets decreased by only 1 basis point, to 4.25% in the fourth quarter of 2013 from 4.26% in the third quarter of 2013. The cost of funds to average earning assets declined by 3 basis point, to 0.41% in the fourth quarter of 2013 from 0.44% in the third quarter of 2013.

Non-interest Income. Total non-interest income, at $2,434,000 in the fourth quarter of 2013, was 28.6% lower than in the fourth quarter of 2012, as mortgage refinance volume continued at much lower levels than year-ago. Gain on sale of mortgages, at $514,000 in the fourth quarter of 2013, decreased 42.5% compared to the third quarter of 2013 and was 69.9% less than the year-ago level. The category of “other” non-interest income, at $482,000 in the fourth quarter of 2013, was 8.6% more than the amount in the third quarter of 2013, primarily due to greater gains on sale of other real estate properties and valuation adjustments on mortgage commitments partially offset by lesser miscellaneous income on commercial loans. This category of “other” non-interest income was 31.4% less than in the fourth quarter of 2012, primarily due to lower gain on sale of other real estate and lesser valuation adjustments on mortgage commitments when compared to that quarter. Net gain on sale of other real estate in the fourth quarter of 2013 was $173,000, and net gains have been recorded in all four quarters of 2013.

Non-interest Expense. Total non-interest expense, at $10,935,000 in the fourth quarter of 2013, was 2.1% lower than the level in the fourth quarter of 2012, even with the above mentioned merger related expenses included, and salaries and employee benefits increasing 3.1% over the level in the fourth quarter of 2012. Occupancy and equipment costs were 3.6% more than the amount in last year’s fourth quarter mostly due to upgrades of computer equipment. FDIC insurance premium expense, at $221,000 in the fourth quarter of 2013, was 13.7% less than the level in the fourth quarter of 2012 due to the timing of expense recognition related to the FDIC’s change in methodology for assessing premiums based on assets rather than deposits. The category of “other” non-interest expense, totaling $3,365,000 in the fourth quarter of 2013 included a $450,000 expense for adding to the reserve for potential put-back claims related to mortgages previously sold in the secondary market. During the fourth quarter of 2013, $644,000 was paid to the Federal Home Loan Mortgage Company (FHLMC) and charged against the reserve in settlement of claims stemming from loans originated prior to January 1 of 2009. At December 31, 2013, this reserve stands at $806,000. In spite of these additional expenses, the category of “other” non-interest expense decreased 13.7% compared to the fourth quarter of 2012, as various other miscellaneous expenses declined and as write-downs of valuations of other real estate owned (OREO) included in the category were only $4,000 in the fourth quarter of 2013, well below the $193,000 amount in the fourth quarter of 2012, and expenses related to the maintenance of OREO properties declined to $60,000 compared to $177,000.

Total Assets. Total assets of Firstbank Corporation at December 31, 2013, were $1.480 billion, a decrease of 1.3% from year-ago. Total portfolio loans of $987 million increased 0.5% from the level at September 30, 2013, and reached a level 2.4% above year-ago. Total portfolio loans have grown for three consecutive quarters. Commercial and commercial real estate loans increased 0.9% in the fourth quarter of 2013, and were 3.9% more than year ago, and real estate construction loans decreased 10.9% from year ago, in spite of a 6.0% increase in the fourth quarter of 2013. Residential mortgage loans decreased 0.4% in the fourth quarter of 2013, but were 2.3% more than year ago. Consumer loans decreased 2.2% in the fourth quarter of 2013 but were 3.3% above year ago. Firstbank continues to have ample capital and funding resources to increase loans on its balance sheet. Total deposits as of December 31, 2013, were $1.233 billion, compared to $1.241 billion at December 31, 2012, a decrease of 0.7%. Core deposits at December 31, 2013, were 0.8% below the year-ago level, and they were flat in the fourth quarter of 2013.

Net Charge-offs. Net charge-offs were $1,609,000 in the fourth quarter of 2013, increasing from $633,000 in the third quarter of 2013 and increasing from $1,331,000 in the fourth quarter of 2012. In the fourth quarter of 2013, net charge-offs annualized represented 0.65% of average loans, compared to 0.26% in the third quarter of 2013 and 0.55% in the fourth quarter of 2012. For full year 2013, net charge-offs declined 30% to $5,173,000 from $7,370,000 in 2012, representing 0.53% of average loans in 2013, improved from 0.75% of loans in 2012.

Allowance and Asset Quality. Asset quality metrics continued to improve in the fourth quarter of 2013, indicating a lesser need for reserves. At the end of the fourth quarter of 2013 the ratio of the allowance for loan losses to loans was 1.82%, compared to 2.00% at September 30, 2013, and 2.21% at December 31, 2012. Performing adjusted loans (troubled debt restructurings, or TDRs) remained at a stable level and were $20,697,000 at December 31, 2013, compared to $20,170,000 at September 30, 2013, and $20,720,000 at December 31, 2012. Loans past due over 90 days and accruing interest were zero at December 31, 2013, compared to $26,000 at September 30, 2013, and reduced from the $37,000 amount at December 31, 2012. Non-accrual loans were $10,077,000 at December 31, 2013, a decrease of 10.1% from the level at September 30, 2013, and a decrease of 35.7% from the $15,668,000 amount at December 31, 2012.

Other real estate owned decreased to $1,838,000 at December 31, 2013, compared to the $2,161,000 level at September 30, 2013, and was down 37.2% from the $2,925,000 level at December 31, 2012.

Equity to Assets Ratio. The ratio of average equity to average assets remained a strong 9.3% in the fourth quarter of 2013, increasing from 9.1% in the third quarter of 2013 and in line with the 9.5% of the year-ago fourth quarter. Firstbank Corporation’s affiliate banks continue to meet or exceed regulatory well-capitalized requirements.

Firstbank Corporation, headquartered in Alma, Michigan, is a bank holding company using a community bank local decision-making format with assets of $1.5 billion and 46 banking offices serving Michigan’s Lower Peninsula. Firstbank Corporation has a pending merger with the similarly sized Mercantile Bank Corporation.

This press release contains certain forward-looking statements that involve risks and uncertainties. When used in this press release the words “anticipate,” “believe,” “expect,” “hopeful,” “potential,” “should,” and similar expressions identify forward-looking statements. Forward-looking statements include, but are not limited to, timing of regulatory approvals and the completion of the merger, future business growth, changes in interest rates, loan charge-off rates, demand for new loans, future profitability, and the resolution of problem loans. Such statements are subject to certain risks and uncertainties which could cause actual results to differ materially from those expressed or implied by such forward-looking statements, including, but not limited to, economic, competitive, governmental, regulatory and technological factors affecting the Company's operations, markets, products, services, interest rates and fees for services. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release.

FIRSTBANK CORPORATION

CONSOLIDATED STATEMENTS OF INCOME

(Dollars in thousands except per share data)

UNAUDITED

(a) Annualized
(b) Period End

(c) Total loans less loans held for sale

FIRSTBANK CORPORATION

CONSOLIDATED BALANCE SHEETS

(Dollars in thousands)

UNAUDITED

(a) Total Loans less loans held for sale

(b) Troubled Debt Restructurings in Call Reports