Copyright sign

A circled C began as a shortcut allowed by United States law. Section 18 of the Copyright Act of 1909 let the owners of pictures, graphic works and sculpture use it in place of the word “Copyright”, and an amendment in 1954 opened it to any published work.

Notice stopped being compulsory when the US joined the Berne Convention on 1 March 1989, because Berne countries protect a work from the moment it is made. Publishers still print © to name the rights holder and the year, and under US law a visible notice stops an infringer from pleading innocent copying to reduce damages.