Now, her most famous co-writers have sold the publishing rights to at least two of her chart-topping singles to a private equity company. It’s a deal that puts a price tag on the hidden half of Swift’s catalog — not the recordings fans and Swift fought over, but the songwriting royalties investors believe will keep paying for decades.

HarbourView Equity Partners bought the publisher’s share of Swift’s songs “Style” and “Ready for It” co-written by Max Martin and Shellback, two of the most recognizable songwriter-producers of the 2000s, and the deal includes songs by Ariana Grande and the Weeknd, among others. 

It’s a transaction Variety exclusively reported on Wednesday to be in the low nine-figure range, according to inside sources, and HarbourView declined to confirm that number and provide details. 

The acquisition doesn’t detract at all from Swift’s existing ownership, but gives HarbourView the slice of copyright that Max Martin and Shellback have as co-writers on “Style”, “Ready for It” and the other pop songs included in the deal. 

HarbourView’s motive to want in on this reflects the three-tiered moneymaking potential of publishing rights: public performances, streaming services and one-time commercial licensing.

This means every time a pop hit like “Style” and “Ready for It” plays in a restaurant or a bar, or is listened to on Spotify, or soundtracks a movie or a commercial, the publisher profits from royalties. This applies to all versions of the song, since the publisher owns the underlying composition and lyrics, so in this case the original “Style” and “Style (Taylor’s Version)”. 

“The industry itself is doing well, and it’s very easily monetized and calibrated,” Barry Massarsky, who leads advisory firm Citrin Cooperman’s music and entertainment valuation services, told Fortune. “Those are the major reasons why there’s such an investment interest in publishing catalogs.”

Massarsky wasn’t involved with the HarbourView deal, but he pointed out that more “mature” catalogs like Max Martin and Shellback’s – who have co-written hit songs for decades – also “trade at a higher multiple” compared to newer ones because there’s more certainty about their returns. 

“Ultimately, things that go up on the charts only have one place to go, and that’s down, so the investor wants to know what happens to the catalog when it reaches what we call a steady state, where the income is reliably set up,” Massarsky said. 

Acquiring Max Martin and Shellback’s copyright shares of Swift’s songs also benefits HarbourView by cutting down on the number of co-writers the company would have to consult to license “Style” and “Ready for It” for films, TV shows and commercials.

“Taylor doesn’t tend to have 10 different songwriters on a song, but then there’s artists who do, and so in that case, you would have to secure permission from all of them,” Tatiana Cirisano, vice president of music strategy at insights firm MIDiA, told Fortune.

HarbourView did not respond to Fortune’s request for comment.