Elon Musk has said his $44 billion deal to buy Twitter is on hold after he queried the number of fake or spam accounts on the social media platform.
He said he was waiting for information supporting calculation that spam or fake accounts do indeed represent less than 5% of users.
Mr. Musk added later that he was still committed to acquisition.
However, analysts speculated he could be seeking to renegotiate the price or even walk away from the takeover.
Mr. Musk's tweets sent Twitter's share price plunging 10% in morning trade in New York.