Slack's stock price jumped 4.02% to $28.59 after Business Insider ran a story on the move, citing a source familiar with the discussions.
However, the story comes on the heels of a Business Insider report on Feb. 10 that IBM was moving all of its 360,000 employees to the work-messaging platform.
The report regarding IBM sent Slack's stock price rocketing more than 15%, triggering a halt in trading shortly before the market close that Monday.
But it wasn't to be.
Slack's stock price later plunged by more than 5% after the San Francisco-based company threw cold water on the story. In a filing with the Securities and Exchange Commission, Slack noted IBM had been its largest customer for years and had been steadily expanding its use of the work-messaging platform.
Slack also stated it would not be revising its financial guidance for the fourth quarter or for its fiscal year ended Jan. 31 - as would be expected if there had been an IBM deal of the size and dramatic nature that had been reported.
The talk of a potential deal with Uber - a customer since 2019, according to Business Insider - comes as Slack wages an intense battle for customers in the work-messaging platform space with Microsoft's (MSFT) - Get Report rival product, Teams.
Slack's stock price slid from a high of $37.50 a share on June 24 to a low of $20.59 on Jan. 20. Despite the setback caused by the erroneous IBM story, shares of Slack have generally been on the upswing since.
A spokesperson for Uber said it had no comment on the Business Insider report.