Salesforce.Com has ruled out bidding for Twitter, with chief executive Marc Benioff quoted as telling the financial daily that "we've walked away" because it wasn't a proper fit.
Twitter shares were down more than six percent to USD 16.68 in early afternoon trading on the New York Stock Exchange.
The tumble came a week after Twitter shares went into a tailspin due to reports that the list of promising suitors was dwindling, with Disney, Apple and Google parent Alphabet not planning any merger moves.
After falling to its lowest point ever earlier this year, Twitter shares were boosted recently on hopes the company will gain traction or a make a promising match with a suitor.
Twitter, which celebrated its 10th anniversary this year, has yet to make a profit. Co-founder Jack Dorsey returned as chief executive last year but has yet to ignite growth, with the number of users stagnating at slightly more than 300 million for several quarters.