Wellington Management Group LLP Reports 6.9% Stake in Mercantile Bank Corporation

On May 15, 2026, Wellington Management Group LLP filed a Schedule 13G indicating a new substantial holding in Mercantile Bank Corporation (MBWM). As of the event date of March 31, 2026, the filer reported beneficial ownership of 1,189,031 shares of Common Stock, representing a 6.9% ownership stake in the company. This filing is a joint submission involving several affiliated entities, including Wellington Group Holdings LLP, Wellington Investment Advisors Holdings LLP, and Wellington Management Company LLP. The shares are held of record by various client accounts managed by investment advisers under the Wellington umbrella. The filing specifies that the shares were acquired in the ordinary course of business and not for the purpose of influencing or changing the control of the issuer. Wellington Management Group LLP serves as the parent holding company for the group, with the reported shares reflecting shared voting power over 1,040,984 shares and shared dispositive power over the full 1,189,031 shares.