(CNN) Taylor Swift called it her "worst case scenario," learning that her music catalog has been sold to a company owned by music manager Scooter Braun.

Claiming she's been bullied by Braun for years, Swift took to Tumblr on Sunday to explain how upset she is that her songs with Big Machine Label Group ended up with Braun , who manages artists such as Justin Bieber, Ariana Grande and the Zac Brown band.

Braun's Ithaca Holdings acquired Big Machine Label Group from founder Scott Borchetta as part of a $300 million deal, reports Billboard . Swift had been signed to the label from her 2006 self-titled debut album through 2017's "Reputation," before moving to Universal Music Group.

The sale prevents Swift from owning the first six albums in her catalog.

"For years I asked, pleaded for a chance to own my work. Instead I was given an opportunity to sign back up to Big Machine Records and 'earn' one album back at a time, one for every new one I turned in," Swift explained.

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