A “secret” composer who has released music under hundreds of different names has been identified as Sweden’s most-listened-to artist on Spotify – pulling in more plays than Britney Spears or Abba.

Johan Röhr, a Stockholm-based musician, has been unmasked as the person behind more than 650 different artists on the streaming service who have been played 15bn times, making him Sweden’s current most-played artist.

According to the Swedish newspaper Dagens Nyheter (DN), which identified the 47-year-old, Röhr has created more than 2,700 songs on the platform under names including “Maya Åström”, “Minik Knudsen”, “Mingmei Hsueh” and “Csizmazia Etel”.

Even by international standards, the newspaper said, the success of Röhr’s multitude of identities puts him among Spotify’s top 100 most-streamed artists – above Michael Jackson, Metallica and Mariah Carey.

Much of his success is believed to be associated with his presence on more than 100 of Spotify’s official instrumental playlists, which the company itself curates.

With names like “peaceful piano” or “stress relief”, such piano-heavy playlists are particularly popular among users seeking music to play in the background while they work, eat meals or relax. Inclusion on one of these highly popular lists can make or break a musician’s career.

Last year Spotify celebrated paying out a record 90bn Swedish kronor (£6.7bn) to the music industry. “Many new and promising artists are now breaking through on Spotify and can finally make a full-time living from music,” Daniel Ek, Spotify’s chief executive, said at the time. “We are very, very proud of that.”

But critics said the success of a few anonymous artists like Röhr who quietly dominate the market is against the spirit of the company’s promise to help small, independent musicians, record companies and composers.

How much Röhr, who has worked as a conductor on pop stars’ tours and on TV, has earned from his agreement with Spotify is not known. However, his private company reportedly made 32.7mn kronor (£2.4m) in 2022, when it had a record year.

He declined to comment to DN and did not respond to the Guardian’s request for comment. But Overtone Studios, the record label which released the music, said Röhr was a “pioneer in the mood music genre” and confirmed that he had used multiple names.

Niklas Brantberg, the chief executive of Overtone Studios, said: “Johan Röhr was the first artist AP Records (now Overtone Studios) worked with. Röhr published music across many different artist profiles and became a pioneer in the mood music space, which is hugely popular today. Many of these are now historical, inactive musical projects and we have already significantly reduced the number of artist profiles actively publishing music.

“We maintain that diversely talented artists should be able to publish music across different artist names – which is commonplace in the industry – spanning various genres and vibes, with different collaborators, and at different points in their musical journey. It allows them to unleash the full range of their creative potential, and Overtone Studios’ focus on providing an equal partnership through a 50/50 royalty split helps our large roster of artists to make a living in the industry.”

Spotify said it did not comment on agreements it has with distributors, which royalties are tied to, but that artists are permitted to use pseudonyms.

A Spotify spokesperson said: “There is an increased interest in functional music created to enhance everyday activities such as relaxation, focus, or studying, and these playlists are created to match the listeners’ demand. This type of music typically exists in Spotify’s Focus hub which limits competition with artists from traditional genres of popular music.

“As listeners’ demand for functional music for relaxation, focus or studying has grown, more artists and record labels are also choosing to produce this type of content. This music, like all other music on Spotify, is licensed from rights holders, and we pay royalties according to the agreements we have with the distributor. Each agreement is unique, but we do not comment on any specifics, nor do we prohibit an artist or band from making music under their own name or under various pseudonyms.”