Unless it's changed in the last year or two, USBank and Iowa State had a massive agreement related to ISU Cards (ID). USBank paid a hefty sum to link the ISU Card to a bank account. As part of the agreement they are allowed to advertise during new student orientation, and would pack Beardshear with workers to get students to sign up while they waited in line to get ID.
USBank used to own the ATMs on campus as well, but this changed three or four years ago (now owned by the Greater Iowa Credit Union).