But the potential windfall is hardly going to change the fortunes of Finn – New Zealand's king of pop.
Even before Boyle covered it, Don't Dream It's Over had been the most performed work by a New Zealand artist overseas in all but one year since it was released, Mushroom Music Publishing general manager Paul McLaney said.
It was on Crowded House's 1986 self-titled debut, credited to Finn. Coldplay, Stevie Wonder, and Faith No More are among the artists who have covered it.
Songwriters generally get about 8c from each copy sold of an album with one of their songs on it.
The Gift has entered the New Zealand album charts at No1 this week, reaching platinum sales of over 15,000 in its first week. Sony is predicting it will sell about five million copies around the world.
That would mean a $400,000 payout for Finn in "mechanical royalties" – money given to an artist every time a recording of their song is made.
Most of the songs on The Gift are Christmas carols and in the public domain. Those likely to receive royalties alongside Finn are Leonard Cohen, for Hallelujah, and Lou Reed for Perfect Day.
Mr McLaney said artists outside Britain generally had little say in whether their songs were recorded by other artists but he doubted Finn would have any qualms about Boyle singing Don't Dream It's Over.
"I don't think it's doing any damage."
Finn had an "unprecedented level of respect" for a New Zealand artist abroad. "He's in that rarefied space of being a pop songwriter but writing songs that reach across the broad range of taste."
Boyle shot to fame on TV programme Britain's Got Talent last year.
Her debut album, I Dreamed a Dream, sold 8.3 million copies worldwide.
Until next time keep rockin'
The 0800 Jukebox crew.