C3.ai shares sank roughly 30 % on Monday after the enterprise-software company issued preliminary first-quarter figures that fell far short of Wall Street estimates. Management said revenue for the quarter ended 31 July is expected to come in at $70.2 million to $70.4 million, down from $87.2 million a year earlier, and projected a GAAP operating loss of nearly $125 million. Chief Executive Officer Thomas Siebel called the sales performance “completely unacceptable,” blaming a reorganisation of the sales force and his own recent health problems for the shortfall. Siebel, who disclosed in July that an autoimmune disease has caused significant vision impairment, said his diminished involvement in the sales process weighed on results. The board and Siebel have initiated a search for a new chief executive, although he said he remains actively engaged in day-to-day operations. C3.ai plans to release full audited results on 3 September. Investor unease over smaller AI-focused software providers deepened after the market closed. BigBear.ai reported second-quarter revenue of $32 million, about 20 % below expectations, and an adjusted loss per share of $0.71 compared with a consensus loss of $0.06. The company cited federal-contracting delays and trimmed its full-year revenue outlook by roughly 11 %. The back-to-back disappointments highlight the difficulty some niche AI vendors face in converting hype into sales at a time when larger technology companies are capturing the bulk of new spending on artificial-intelligence tools.