As near as I can tell, it’s always been owned by Cliqz, who produced some privacy-focused browsers (named Dawn or Lumen) and a search engine (Tailcat) that was ultimately purchased by Brave. The whole thing is majority owned by a German media group, Hubert Burda Media, and while its missions towards increased privacy seem to be sincere, I don’t know if I’d trust them implicitly.

All that said, the main project looks to be open sourced under a GPL3 license, so distrust and verify: https://github.com/ghostery