Equal Housing Opportunity. Federally insured by NCUA. GreenState Credit Union is a member owned financial cooperative with 18 office locations. Since being organized in 1938, GreenState has grown to over $5.5 billion in assets and 200,000 members. Membership is open to anyone living or working in Iowa and 4 Illinois Counties, as well as direct relatives of current members and University of Iowa students, staff, and alumni.