Dive Brief: North Liberty, Iowa-based GreenState Credit Union is buying two banks — Oak Brook, Illinois-based Oxford Bank & Trust and Omaha-based Premier Bank, the credit union announced Tuesday. The deals, each expected to close by the fourth quarter of 2021 — pending regulatory approval — mark the third and fourth banks to be bought by a credit union this year. Credit union purchases of banks typically draw objections from trade groups such as the Independent Community Bankers of America (ICBA), which argues credit unions’ tax-exempt status allows them to offer a higher purchase price for acquisitions than banks can, and lets them grow more freely.