Whilst hunting for links through to the GRW cut-up engine, I came across this, which led me to this:

"Who does own the publishing rights to "Happy Birthday to You"? They were acquired by a New York accountant named John F. Sengstack when he bought the Clayton F. Summy Company in the 1930s; Sengstack eventually relocated the company to New Jersey and renamed it Birch Tree Ltd. in the 1970s. Warner Chappell (a Warner Communications division), the largest music publisher in the world, purchased Birch Tree Ltd. in late 1998 for a reported sale price of $25 million; the company then became Summy-Birchard Music, now a part of the giant AOL Time Warner media conglomerate. According to David Sengstack, president of Summy-Birchard, "Happy Birthday to You" brings in about $2 million in royalties annually, with the proceeds split between Summy-Birchard and the Hill Foundation. (Both Hill sisters died unmarried and childless, so the Hill Foundation's share of the royalties have presumably been going to charity or to nephew Archibald Hill ever since Patty Hill passed away in 1946.) "

I wish I could find more information on what the Hill Foundation does, but Archibald, a linguistics professor from Texas, sadly passed away in 1992:

"He used to point to this or that and say something to the effect that "'Happy Birthday' bought that." Many have speculated how much "Happy Birthday" subsidized the LSA between 1950 and 1968 or the Hill Library in the Department of Linguistics."

And it seems that Archibald didn't have any children, so where now for the estimated $20,000 per annum the song made for him?