Who paid for the letters on the Hollywood sign?

Harry Chandler, publisher of the Los Angeles Times.

http://www.hollywoodsign.org/the-history-of-the-sign/1923-a-sign-is-born/

When the sign showed signs of deterioration in 1978 a public campaign restored the sign, the following nine donors gave $27,777.77 each (which totaled $250,000):
H: Terrence Donnelly (publisher of the Hollywood Independent Newspaper)
O: Giovanni Mazza (Italian movie producer)
L: Les Kelley (originator of the Kelley Blue Book)
L: Gene Autry (actor)
Y: Hugh Hefner (founder of Playboy magazine)
W: Andy Williams (singer)
O: Warner Bros. Records
O: Alice Cooper (singer), who donated in memory of close friend and comedian Groucho Marx, and who joked that he would also donate an "O" from his last name
D: Dennis Lidtke (businessman)[9]:166-167
https://en.wikipedia.org/wiki/Hollywood_Sign