Infinity Federal Credit Union has been open since 1921. It's the 5th largest credit union in Maine with assets totaling $333.87 Million and providing banking services to more than 18,000 members. Membership: The credit union is a community-based financial institution. People living, working, or worshipping in the credit union's geographic area can become a member and access banking services. Membership is also open to immediate family of current members.