Music copyrights and royalties are already a sordid and messy affair, and that's without the added complication of streaming. There's artists, publishers, songwriters, and any number of other folks who have some stake in any given song, which means that there are just that many more people who can get lost in the shuffle as works move across media. Now add in a group that kinda exists but not really, with real songs for a fake documentary that's actually one of the great works of comedy filmmaking of the past (if you don't believe me, ask The Guardian) and you can find a particularly complex case of copyright and music.
The creators behind This is Spinal Tap have reached a settlement with Universal Music Group over royalties and rights to the soundtrack recordings from the film, resolving a lawsuit dating back to 2016 over what the group claimed were unpaid royalties over a period of nearly twenty years. The suit was initially pursued by Harry Shearer, the group's pretend/real bassist, in the amount of $125 million, alleging that the rightsholders only paid out $98 in royalties from soundtrack sales and $81 from merchandise from the period from 1989 to 2006 — little more than you could hope to make following a puppet show. While that suit, which the other creators were eventually added to, was dismissed, a series of individual cases were soon launched by each of the creators
As with any lawsuit of this type, there was the usual claims as to what was done by whom, what information and payments were withheld and thus owed, and what standing the plaintiffs had to even bring the case, all of which usually engenders no small amount of ill will between the opposing parties. That's why it's surprising to see that this case reached such an amicable resolution, one in which a studio and label gives more than would traditionally be expected, and creators get more than you would have guessed at the out.
In the terms of the settlement, Spinal Tap's songs (including classics like "Stonehenge" and a few a bit too prurient for this space) will continue to be distributed by Universal Music Group for the time being, with the rights reverting to the creators at some point in the future. It's a boon to both the creators and fans of the film that the right people are getting due compensation for their work, and that this particular case wasn't one best left unsolved.