Significant Accounting Policies

9 Months Ended

Sep. 30, 2011

Significant Accounting Policies [Abstract]

SIGNIFICANT ACCOUNTING POLICIES

1. SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation: The unaudited financial statements for the nine months ended September 30, 2011 include the consolidated results of operations of Mercantile Bank Corporation and its consolidated subsidiaries. These subsidiaries include Mercantile Bank of Michigan (“our bank”) and our bank’s three subsidiaries, Mercantile Bank Mortgage Company, LLC (“our mortgage company”), Mercantile Bank Real Estate Co., LLC (“our real estate company”), and Mercantile Insurance Center, Inc. (“our insurance center”). These consolidated financial statements have been prepared in accordance with the instructions for Form 10-Q and Item 303(b) of Regulation S-K and do not include all disclosures required by accounting principles generally accepted in the United States of America for a complete presentation of our financial condition and results of operations. In the opinion of management, the information reflects all adjustments (consisting only of normal recurring adjustments) which are necessary in order to make the financial statements not misleading and for a fair presentation of the results of operations for such periods. The results for the period ended September 30, 2011 should not be considered as indicative of results for a full year. For further information, refer to the consolidated financial statements and footnotes included in our annual report on Form 10-K for the year ended December 31, 2010.

We formed a business trust, Mercantile Bank Capital Trust I (“the trust”), in 2004 to issue trust preferred securities. We issued subordinated debentures to the trust in return for the proceeds raised from the issuance of the trust preferred securities. The trust is not consolidated, but instead we report the subordinated debentures issued to the trust as a liability.

Earnings Per Share: Basic earnings per share is based on the weighted average number of common shares and participating securities outstanding during the period. Diluted earnings per share include the dilutive effect of additional potential common shares issuable under our stock-based compensation plans and our common stock warrant, and are determined using the treasury stock method. Our unvested restricted shares, which contain non-forfeitable rights to dividends whether paid or accrued (i.e., participating securities), are included in the number of shares outstanding for both basic and diluted earnings per share calculations. In the event of a net loss, our unvested restricted shares are excluded from the calculation of both basic and diluted earnings per share.

Approximately 70,000 unvested restricted shares were included in determining both basic and diluted earnings per share for the three and nine months ended September 30, 2011. In addition, stock options and a stock warrant for approximately 48,000 and 616,000 shares of common stock, respectively, were included in determining diluted earnings per share for the three and nine months ended September 30, 2011. Stock options for approximately 197,000 shares of common stock were antidilutive and not included in determining diluted earnings per share for the three and nine months ended September 30, 2011.

Due to our net loss for the 2010 periods, approximately 87,000 unvested restricted shares were not included in determining both basic and diluted earnings per share for the three and nine months ended September 30, 2010. In addition, stock options and a stock warrant for approximately 283,000 and 616,000 shares of common stock, respectively, were antidilutive and not included in determining diluted earnings per share for the three and nine months ended September 30, 2010. Weighted average diluted common shares outstanding equals the weighted average common shares outstanding during the three and nine months ended September 30, 2010 due to the net loss recorded during those time periods.

Allowance for Loan Losses: The allowance for loan losses (“allowance”) is a valuation allowance for probable incurred credit losses. Loan losses are charged against the allowance when we believe the uncollectability of a loan is confirmed. Subsequent recoveries, if any, are credited to the allowance. We estimate the allowance balance required using past loan loss experience, the nature and volume of the portfolio, information about specific borrower situations and estimated collateral values, economic conditions and other factors. Allocations of the allowance may be made for specific loans, but the entire allowance is available for any loan that, in our judgment, should be charged-off.

A loan is impaired when, based on current information and events, it is probable we will be unable to collect the scheduled payments of principal and interest when due according to the contractual terms of the loan agreement. Factors considered in determining impairment include payment status, collateral value and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. We determine the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of delay, the reasons for delay, the borrower’s prior payment record and the amount of the shortfall in relation to the principal and interest owed. Impairment is measured on a loan-by-loan basis for commercial and construction loans by either the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s obtainable market price or the fair value of collateral if the loan is collateral dependent. Large groups of smaller balance homogeneous loans are collectively evaluated for impairment. We do not separately identify individual residential and consumer loans for impairment disclosures.

Troubled Debt Restructurings: A loan is accounted for as a troubled debt restructuring if we, for economic or legal reasons, grant a concession to a borrower considered to be experiencing financial difficulties that we would not otherwise consider. A troubled debt restructuring may involve the receipt of assets from the debtor in partial or full satisfaction of the loan, or a modification of terms such as a reduction of the stated interest rate or balance of the loan, a reduction of accrued interest, an extension of the maturity date or renewal of the loan at a stated interest rate lower than the current market rate for a new loan with similar risk, or some combination of these concessions. Troubled debt restructurings can be in either accrual or nonaccrual status. Nonaccrual troubled debt restructurings are included in nonperforming loans. Accruing troubled debt restructurings are generally excluded from nonperforming loans as it is considered probable that all contractual principal and interest due under the restructured terms will be collected.

In accordance with current accounting guidance, loans modified as troubled debt restructurings are, by definition, considered to be impaired loans. Impairment for these loans is measured on a loan-by-loan basis similar to other impaired loans as described above under “Allowance for Loan Losses.” Certain loans modified as troubled debt restructurings may have been previously measured for impairment under a general allowance methodology (i.e., pooling), thus at the time the loan is modified as a troubled debt restructuring the allowance will be impacted by the difference between the results of these two measurement methodologies. Loans modified as troubled debt restructurings that subsequently default are factored into the determination of the allowance in the same manner as other defaulted loans.

Derivatives: Derivative financial instruments are recognized as assets or liabilities at fair value. The accounting for changes in the fair value of derivatives depends on the use of the derivatives and whether the derivatives qualify for hedge accounting. Used as part of our asset and liability management to help manage interest rate risk, our derivatives have historically consisted of interest rate swap agreements that qualified for hedge accounting. In June 2011, we simultaneously purchased and sold an interest rate cap, a structure commonly referred to as a “cap corridor”, which does not qualify for hedge accounting. We do not use derivatives for trading purposes.

Changes in the fair value of derivatives that are designated, for accounting purposes, as a hedge of the variability of cash flows to be received on various loans and are effective are reported in other comprehensive income. They are later reclassified into earnings in the same periods during which the hedged transaction affects earnings and are included in the line item in which the hedged cash flows are recorded. If hedge accounting does not apply, changes in the fair value of derivatives are recognized immediately in current earnings as interest income or expense.

If designated as a hedge, we formally document the relationship between derivatives as hedged items, as well as the risk-management objective and the strategy for undertaking hedge transactions. This documentation includes linking cash flow hedges to specific assets on the balance sheet. If designated as a hedge, we also formally assess, both at the hedge’s inception and on an ongoing basis, whether the derivative instruments that are used are highly effective in offsetting changes in cash flows of the hedged items. Ineffective hedge gains and losses are recognized immediately in current earnings as noninterest income or expense. We discontinue hedge accounting when we determine the derivative is no longer effective in offsetting changes in the cash flows of the hedged item, the derivative is settled or terminates, or treatment of the derivatives as a hedge is no longer appropriate or intended.

Adoption of New Accounting Standards: In January 2010, the Financial Accounting Standards Board (“FASB”) issued ASU 2010-06, Improving Disclosure about Fair Value Measurements. This ASU requires new disclosures on the amount and reason for transfers in and out of Level 1 and Level 2 recurring fair value measurements. The ASU also requires disclosure of activities (i.e., on a gross basis), including purchases, sales, issuances, and settlements, in the reconciliation of Level 3 recurring fair value measurements. The ASU clarifies existing disclosure requirements on levels of disaggregation and disclosures about inputs and valuation techniques. The new disclosure regarding Level 1 and Level 2 recurring fair value measurements and clarification of existing disclosures were effective beginning January 1, 2010. Upon adoption of those portions of the ASU in our 2010 first quarter, we began providing the required disclosures as currently presented in Note 11. The disclosures about the reconciliation of information in Level 3 recurring fair value measurements were required beginning January 1, 2011. There was no effect on our fair value disclosures presented in Note 11 upon adoption of the final portion of the ASU in our 2011 first quarter, as we currently have no Level 3 recurring fair value measurements.

In July 2010, the FASB issued ASU 2010-20, Disclosure about the Credit Quality of Financing Receivables and the Allowance for Credit Losses. In order to provide greater transparency, this ASU requires significant new disclosures on a disaggregated basis about the allowance for credit losses (i.e., allowance for loan losses for banks) and the credit quality of financing receivables (i.e., loans for banks). Under the ASU, a rollforward schedule of the allowance for loan losses, with the ending allowance balance further disaggregated on the basis of the impairment method, along with the related ending loan balance and significant purchases and sales of loans during the period are to be disclosed by portfolio segment. Additional disclosures are required by class of loan, including credit quality, aging of past due loans, nonaccrual status and impairment information. Disclosure of the nature and extent of troubled debt restructurings (“TDR”) that occurred during the period and their effect on the allowance for loan losses as well as the effect on the allowance of TDRs that occurred within the prior twelve months and that defaulted during the current reporting period will also be required. The disclosures are to be presented at the level of disaggregation that management uses when assessing and monitoring the loan portfolio’s risk and performance. The majority of disclosures required as of the end of a reporting period were effective as of December 31, 2010. Upon adoption of those portions of the ASU on December 31, 2010, we began providing the required end of period disclosures as currently presented in Note 3. The disclosures about activity were effective January 1, 2011. Upon adoption of the final portion of the ASU in our 2011 first quarter, we began providing the required activity disclosures, with the exception of the new TDR related disclosures, as currently presented in Note 3. In January 2011, the FASB issued ASU 2011-01, Deferral of the Effective Date of Disclosures about Troubled Debt Restructurings in Update No. 2010-20, which temporarily deferred the effective date for disclosures related to TDRs. Beginning with the 2011 third quarter, we began providing the required TDR disclosures as presented in Note 3.

In April 2011, the FASB issued ASU 2011-02, A Creditor’s Determination of Whether a Restructuring is a Troubled Debt Restructuring, to clarify when a loan modification or restructuring is considered a TDR. When performing this evaluation under the ASU, a creditor must use judgment to determine whether (1) the debtor (i.e., the borrower) is experiencing financial difficulty, and (2) the lender has granted a concession to the borrower. The ASU amends current guidance to include indicators that a lender should consider in determining whether a borrower is experiencing financial difficulties. It further clarifies that a borrower could be experiencing financial difficulty even if it is not currently in default but default is probable in the foreseeable future. With respect to whether the lender has granted a concession to the borrower, the ASU indicates (1) a borrower’s inability to access funds at a market interest rate for debt with similar risk characteristics as the restructured debt indicates that the modification was executed at a below-market rate and therefore may indicate a concession was granted, (2) a modification that permanently or temporarily increases a loan’s contractual interest rate does not preclude it from being considered a concession because the rate may still be below the market interest rate for new debt with similar risk characteristics, and (3) a modification that results in a delay in payment that is insignificant is not considered to be a concession. The ASU also clarifies that a creditor is precluded from using the borrower’s effective interest rate test when performing this evaluation. For TDR identification and disclosure purposes, the guidance became effective for our 2011 third quarter and was applied retrospectively to modifications occurring on or after January 1, 2011 that remained outstanding at September 30, 2011. The effect of the change in the method of calculating impairment was reflected in our 2011 third quarter. The ASU requires disclosure of the total recorded investment and allowance for loan losses for newly identified TDRs, based on the new guidance, as of September 30, 2011. Beginning in our 2011 third quarter, we disclosed the previously deferred TDR activity related disclosures required by ASU 2010-20 in Note 3.

In April 2011, the FASB issued ASU 2011-03, Reconsideration of Effective Control for Repurchase Agreements, to improve financial reporting of repurchase agreements and other agreements that both entitle and obligate a transferor to repurchase or redeem financial assets on substantially the agreed upon terms. This ASU eliminates consideration of the transferor’s ability to fulfill its contractual rights and obligations from the criteria, as well as related implementation guidance (i.e., that it possesses adequate collateral to fund substantially all the cost of purchasing replacement financial assets), in determining effective control, even in the event of default by the transferee. Other criteria applicable to the assessment of effective control are not changed by this new guidance. This ASU is effective January 1, 2012. We do not expect the adoption of this new ASU to have a material effect on our results of operations or financial position.

In May 2011, the FASB issued ASU 2011-04, Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRS, to align the fair value measurement and disclosure requirements in U.S. GAAP and International Financial Reporting Standards (“IFRSs”). Many of the amendments in this ASU will not result in a change in requirements but simply clarify existing requirements. The amendments in this ASU that do not change a principle or requirement for measuring fair value or disclosing information about fair value measurements include the following: (1) the ASU permits an exception for measuring fair value when a reporting entity manages its financial instruments on the basis of its net exposure, rather than gross exposure, to those risks; (2) the ASU clarifies that the application of premiums and discounts in a fair value measurement is related to the unit of account for the asset or liability being measured at fair value and specifically prohibits blockage discounts for Level 2 and 3 investments; and (3) the amendments expand fair value measurement disclosures. The more significant new disclosures include: (1) for all Level 3 fair value measurements, quantitative information about significant unobservable inputs used as well as a qualitative discussion about the sensitivity of recurring Level 3 fair value measurements; (2) transfers between Level 1 and Level 2 fair value measurements on a gross basis, including the reasons for those transfers; and (3) the categorization by level of the fair value hierarchy for items that are not measured at fair value in the balance sheet but for which the fair value is required to be disclosed (e.g., held-to-maturity securities and loans). The ASU is to be applied prospectively and is effective January 1, 2012. We do not expect the adoption of this new ASU to have a material effect on our results of operations or financial position.

In June 2011, the FASB issued ASU 2011-05, Presentation of Comprehensive Income, to improve the comparability, consistency and transparency of financial reporting and to increase the prominence of items reported in other comprehensive income. The ASU eliminates the option to present components of other comprehensive income as part of the Statement of Changes in Shareholders’ Equity. Instead, all changes in shareholders’ equity must be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements. In the single continuous statement approach, the statement should present the components of net income and total net income, the components of other comprehensive income and total other comprehensive income, and a total for comprehensive income. In the two-statement approach, the first statement should present the components of net income and total net income followed consecutively by a second statement that should present the components of other comprehensive income, a total for other comprehensive income and a total for comprehensive income. Also known as “recycling,” companies will also be required to display reclassification adjustments and their effect on net income and other comprehensive income in the statement(s) in which they appear. The ASU does not change certain other current requirements including items that constitute net income and other comprehensive income. The ASU is to be applied retrospectively and is effective January 1, 2012. We are currently evaluating the two presentation approaches permitted by the ASU. On October 21, 2011, the FASB decided to defer the above-described presentation of reclassification adjustments until further consideration.