Nvidia’s stock slid more than 4% on Monday, the first trading day after its board said it would investigate CEO Jensen Huang over his relationship with Alice Huang, an executive U.S. intelligence believes was spying for China.

Securities lawyers were already moving. At least four firms, including Schall, Brown & Schwartz and Levi & Korsinsky, announced investigations Monday into whether Nvidia misled investors. Robert Bartlett, a Stanford Law professor and securities law expert, expects them to have plenty of company.