Twitter shares plummeted last week as potential suitors threw in the towel to exit from the acquisition process.

Twitter stock, which had been marching steadily upward since news of a possible sale surfaced in September, fell 20 percent to $19.85. Google no longer plans to make a bid, technology-news site Recode said. Walt Disney also will now not put in an offer. Salesforce has not formally withdrawn

Salesforce.com is still seen as a possible bidder by some observers, but CEO Mark Benioff has described Twitter as having “severe issues”.