Ames-based First National Bank has entered into a stock purchase and subsequent merger agreement to acquire Clarke County State Bank in Osceola. The agreement provides for the purchase of 100 percent of the outstanding stock of Clarke County State Bank, which has assets of approximately $111 million. The Clarke County State Bank offices in Osceola and Murray will become offices of First National Bank through this merger and will be led by David Selene, president at Clarke County State Bank, along with his management team. First National Bank is a subsidiary of Ames National Corp., which has $1.4 billion in assets. The transaction is expected to close in the third quarter of 2018, subject to regulatory approval and other standard closing conditions.