Twitter's share price has dropped by 20 per cent in pre-market trading.
The social network's stock has been all over the place this week - first soaring on rumours of takeover interest from an array of companies including Google and Disney.
However, as takeover talk cooled, the share price nosedived, tumbling by 16 per cent before the market opened yesterday.
Salesforce chief executive Mark Benioff has publicly expressed his interest in Twitter in recent days, but stopped short of saying the company had decided on a bid.
Analysts said he downplayed the possibility in a meeting with investors on Wednesday, sending Salesforce shares up about four per cent.