What is the legal test for whistleblower retaliation under Sarbanes-Oxley?

Whistleblower retaliation claims under Sarbanes-Oxley "are governed by a burden-shifting procedure under which the plaintiff is first required to establish a prima facie case of retaliatory discrimination." Tides v. Boeing Co., 644 F.3d 809, 813-14 (9th Cir. 2011). To make a prima-facie showing, the plaintiff must show that (1) the plaintiff engaged in protected activity; (2) the plaintiff's employer knew, actually or constructively, of the protected activity; (3) the plaintiff suffered an unfavorable personnel action; and (4) the circumstances raise an inference that the protected activity was a contributing factor to the unfavorable action. Id. at 814 (citing Van Asdale, 577 F.3d at 996); see also 29 C.F.R. 1980.104(e)(2)(i)-(iv). If the plaintiff makes this showing, then "the employer assumes the burden of demonstrating by clear and convincing evidence that it would have taken the same adverse employment action in the absence of the plaintiff's protected activity." Van Asdale, 577 F.3d at 996.