Series (United States Currency) - Since 1928

Since 1928

Series 1928 was the first series of modern, small-sized notes issued. Since then, the series year has been changed when there is a major design change to a bill; a minor design change is indicated by a letter suffix being added to the series year. Major design changes were rare until 1974, when William E. Simon became Secretary of the Treasury. Before 1974, a change to either the signature of the Secretary of the Treasury or the Treasurer was considered a minor change; after 1974, a new Secretary of the Treasury was considered a major change. (The only exception to this was in 1979, G. William Miller's signature appeared on Series 1977A instead of Series 1979.) A change in Treasurer is still considered a minor change. Changes in design, such as the recent changes to the $20 bill to deter counterfeiting, are still considered major changes.