Taylor Swift says she is "sad" and "grossed out" after entrepreneur Scooter Braun acquired her back catalogue and has accused the 38-year-old of being behind "incessant, manipulative bullying".
Braun, manager of Justin Bieber and Ariana Grande, owns Ithaca Holdings which purchased Big Machine Label Group at the weekend.
Swift signed for Big Machine, founded by former Universal executive Scott Borchetta, in 2005 and moved to Universal Music Group in November last year.
Writing on Tumblr, she said: "I learned about Scooter Braun's purchase of my masters as it was announced to the world.
"All I could think about was the incessant, manipulative bullying I've received at his hands for years."
Braun's wife Yael Braun said he was "anything but a bully", adding: "Interesting that the man you're so 'grossed out' by believed in you more than you believe in yourself."
The singer-songwriter, whose new album Lover is released in August, said: "I am now signed to a label that believes I should own anything I create.
"Thankfully, I left my past in Scott's (Borchetta, founder of Big Machine) hands and not my future.
"And hopefully, young artists or kids with musical dreams will read this and learn about how to better protect themselves in a negotiation."
Borchetta said he wanted to "set things straight" in a post entitled So, It's Time For Some Truth on Big Machine's website.
He wrote that Swift's father Scott Swift was a shareholder in Big Machine and was alerted about the pending deal on June 25.
He added: "We then had a final call on Friday, June 28th in which the transaction passed with a majority vote and 3 of the 5 shareholders voting 'yes' with 92% of the shareholder's vote.
"Out of courtesy, I personally texted Taylor at 9:06pm, Saturday, June 29th to inform her prior to the story breaking on the morning of Sunday, June 30th so she could hear it directly from me."
Australian Associated Press