Every music stream generates two royalties: one for the recording and one for the underlying work. The work's mechanical royalties in the US are collected by The MLC, a nonprofit created by the 2018 Music Modernization Act. If songs aren't registered, metadata is incorrect, or other issues exist, royalties never reach their owners and instead accumulate in an unallocated pool called the 'black box'.

The MLC currently holds over $656M in unclaimed royalties. Starting in January 2027, The MLC must distribute this money through a process called 'market share,' paying it pro-rata to artists, songwriters, and publishers already in the system. The first payout begins at $6.41M in January 2027, with subsequent monthly distributions totaling $76.61M over the next 12 months.

A new self-service tool helps artists and songwriters check if their recordings are registered and matched with The MLC. Users paste a Spotify artist link or search by name, and the tool checks each recording against The MLC's public data, showing whether songs are fully claimed, partially claimed, registered but unmatched, or missing entirely. It also estimates potential dollars stuck in the black box.

The tool was built by Doubly, an independent publishing administrator. While they have a commercial interest, the team emphasizes the tool is free, requires no signup, and provides actionable reports without needing assistance from their company.