Industry tracker Billboard cited anonymous sources in first reporting the sale of the catalogue that includes hits like “Under The Bridge,” “Californication” and “Snow (Hey Oh).”

Neither Hipgnosis nor the band’s representatives immediately responded on Tuesday to AFP requests for comment.

As most of the songs were written collectively by band members Flea, Anthony Kiedis, John Frusciante and Chad Smith, the purchase required joint approval.

According to Billboard, Hipgnosis sold nine million new ordinary shares at US$1.66 per share on April 29 to finance the deal, which brought in US$14 million.

The company headed by music magnate Merck Mercuriadis debuted on the London Stock Exchange in July 2018, and has dropped well over US$1 billion on catalog acquisitions including from Neil Young, Blondie, Shakira and RZA.

The latest sale is part of a song rights purchasing boom as financial markets increasingly are drawn to the lucrative portfolios as an asset class.

In many cases, the transactions have come at staggering prices.

Bob Dylan sold his full publishing catalog for a reported sum of US$300 million to Universal Music Publishing Group, while Stevie Nicks of Fleetwood Mac sold a majority stake in her catalogue reportedly for US$100 million.

The owners of a song’s publishing rights receive a cut in a number of scenarios, including radio play and streaming, album sales, and use in advertising and movies.

The sales allow artists to receive immediate payouts rather than wait for those earnings – necessary for some as the pandemic has thwarted performances.