No. For it to be securities fraud, Arm would need to make a materially false statement of fact that misleads investors. Naming the CPU in this way doesn't clear the bar because:
a) the name is clearly product brand, similar to how macOS Lion, or Microsoft Windows, or Ford Mustang, or Yves Saint Laurent Black Opium don't mean literally what they say)
b) Arm explicitly defines it as silicon "designed to power the next generation of AI infrastructure", with the technical specs fully disclosed
c) sophisticated investors, the relevant standard for securities fraud, can read a spec sheet
d) Arms' EVP said "We think that the CPU is going to be fundamental to ultimately achieving AGI", framing it as contribution towards AGI, not AGI itself