Was Happy Birthday Copyrighted?
“Happy birthday” was copyright protected from 1935 until Sept 2015. During that time you couldn’t sing happy birthday publicly without paying royalties. This is why many businesses sing a variation of the song when they celebrate people’s birthdays.
This PBS video from when “Happy Birthday to You” was still copyrighted discusses the background on “Happy Birthday” and it’s copyright.
In 1988, Warner/Chappell Music purchased the company owning the copyright for US $25 million, with the value of “Happy Birthday” estimated at US $5 million. “Happy Birthday to You” had reportedly been generating some $2 million in royalties per year for Warner/Chappell Music.