"Happy Birthday" was in the news this morning (Reuters).

A federal lawsuit was filed Thursday asking that the song be declared in the public domain and that Warner/Chappell Music return the millions of dollars "in unlawful licensing fees" that they have received for its performance.
According to the lawsuit, Warner/Chappell receives some $2 million annually in fees for its performance.

Although the song as published in 1893 by Patty and Mildred Hill had the words "Good Morning to All," "the public began singing "Happy Birthday" soon after."

According to Warner, Clayton Summy bought the rights to "Good Morning to All" from the Hill sisters in 1893. The rights were obtained by Birch Tree Ltd., a company that traces its roots to Summy. Birch Tree was acquired by Time Warner in 1998.

The Warner Music interests were sold to the present holder, Access Industries, in 2011.