Cybersecurity stocks were falling sharply on Thursday after the sector rebounded earlier in the week, boosted by a new Anthropic project. Palo Alto Networks was down 3.9%, CrowdStrike Holdings was off 7.5%, Zscaler tumbled 11%, SailPoint dropped 11%, and Fortinet slid 3.4%. Aside from concerns that improving AI models can replace critical software functions, some investors are focused on how AI, and the implementation of AI agents, introduces more complex security challenges.