Staff at the Pinnacle Bank branch in Lincoln reported the Monday morning incident to police. The Lincoln Journal Star reports that bank employees say the man was adamant that the bill was real despite tellers' attempts to convince him otherwise.
The man eventually left with the bill, but without a new account.
Police are reviewing surveillance video to try to identify the man. Police say they want to check on his welfare and make sure he was not the victim of a crime.
The largest denomination note ever issued for public circulation was the $10,000 bill.