C3 AI stock falls 20% as CEO Siebel calls preliminary sales numbers 'completely unacceptable'

Shares of the enterprise artificial intelligence company C3 AI tumbled more than 20% Monday after it announced preliminary financial results and a restructuring of its global sales and services organization.

C3 AI said Friday that it expects to report revenue between $70.2 million and $70.4 million for its fiscal first quarter 2026, though those figures are unaudited, preliminary estimates. The company reported $87.2 million in revenue during the same period a year earlier.

Thomas Siebel, C3 AI's CEO, said in a statement that sales results during the quarter were "completely unacceptable." He attributed the performance to the "disruptive effect" of the reorganization, as well as his ongoing health issues.

The company expects to report a GAAP loss from operations for the quarter between $124.7 million and $124.9 million, a much wider loss than a year ago, when C3 AI had a loss of $72.59 million.

"Unfortunately, dealing with these health issues prevented me from participating in the sales process as actively as I have in the past," Siebel said in a statement. "With the benefit of hindsight, it is now apparent that my active participation in the sales process may have had a greater impact than I previously thought."

Siebel announced in July that he was diagnosed with an autoimmune disease earlier this year, resulting in "significant visual impairment." C3 AI's board and Siebel have kicked off a search for the company's next chief executive.

C3 AI said its sales and services restructuring is complete, and Siebel said his health has "improved dramatically" except for his vision impairment. He said he is feeling strong and fully engaged, and will work to quickly identify "excellent" CEO candidates.

"I am confident the company is positioned to accelerate going forward," Siebel said.

The company is scheduled to hold a conference call for first quarter results on Sept. 3 at 5 p.m. ET.