Ai was released Wednesday, but the whereabouts of his driver, accountant, assistant and a designer arrested with him had been unclear, the BBC reported Saturday.
The BBC said a source close to the artist said the others have been released on bail.
Ai's arrest on what some said were trumped up charges sparked a global campaign for his release.
Zhang Jinsong, Hu Mingfen, Wen Tao and Liu Zhenggang were released on bail Thursday and Friday, the BBC reported.
Ai is barred from discussing his case and he can't leave Beijing without permission. He also reportedly was barred from using the social networking site Twitter to criticize the Chinese government.