The company confirmed in a September 17th statement that it no longer represents Britney, who was officially with the management company for one month.
Asked if Spears had a new manager lined up, a representative of a PR firm fielding calls for The Firm told Pollstar, "No."
Spears leaves The Firm a week after a less-than-stellar performance at the MTV Video Music Awards.
"We believe Britney is enormously talented, and has made a terrific record," The Firm said in a statement. "But current circumstances have prevented us from properly doing our job."