Copyright Law in the United States: Before 1989, the use of a copyright notice – consisting of the
copyright symbol (©, the letter
C inside a circle), the abbreviation "Copr.", or the word "Copyright", followed by the year of the first publication of the work and the name of the copyright holder – was part of U. S. statutory requirements.
[24][25] Several years may be noted if the work has gone through substantial revisions. The proper copyright notice for sound recordings of musical or other audio works is a
sound recording copyright symbol (℗, the letter
P inside a circle), which indicates a sound recording copyright, with the letter
P indicating a "phonorecord". Similarly, the phrase
All rights reserved was once required to assert copyright.In 1989 the United States enacted the
Berne Convention Implementation Act, amending the 1976 Copyright Act to conform to most of the provisions of the Berne Convention. As a result, the use of copyright notices has become optional to claim copyright, because the Berne Convention makes copyright automatic.
[26] However, the lack of notice of copyright using these marks may have consequences in terms of reduced damages in an infringement lawsuit – using notices of this form may reduce the likelihood of a defense of "innocent infringement" being successful.[27]