The agreement, slated to close in the first quarter of 2027, marks a significant expansion for the Houston-based Third Coast. By absorbing the Oklahoma City-headquartered Great Plains, the bank secures an immediate entry into the Oklahoma market while bolstering its existing footprint in Dallas. The combined franchise will operate 23 branches across both states.

Under the terms, Great Plains will function as a division of Third Coast, preserving its established brand identity. Ownership stakes will shift accordingly, with Third Coast shareholders controlling 78% of the new entity, while Great Plains shareholders hold the remaining 22%. To ensure continuity, Great Plains Chief Executive Mark Russell will remain in a leadership capacity, and two representatives from the acquired firm will join the combined board of directors. Third Coast Chief Executive Bart Caraway noted that the integration leverages the cultural alignment of two relationship-driven institutions to enhance overall lending capacity.