Elon Musk on Friday put his $44-billion deal for Twitter Inc temporarily on hold

Shares of the social media company fell 17.7% to $37.10 in premarket  trading, their lowest level since Musk disclosed his stake in the company in early April

The implied probability of the deal closing at the agreed price fell  below 50% for the first time on Tuesday, when Twitter shares dropped below $46.75.

Twitter had earlier this month estimated that false or spam accounts  represented fewer than 5% of its monetizable daily active users

"Twitter deal temporarily on hold pending details supporting calculation  that spam/fake accounts do indeed represent less than 5% of users,"  Musk tweeted on Friday.

Musk, the world's richest man and a self-proclaimed free speech  absolutist, had said that one of his priorities would be to remove "spam  bots" from the platform.