From Marlow v. v. Allianz Life Ins. Co. of N. Am., 2009 U.S. Dist. LEXIS 43502 (D. Colo. May 12, 2009):

[E]ven if Plaintiff had stated a § 1962(c) violation, he has not sufficiently alleged that his injuries were caused by that violation. Causation in the RICO context requires a plaintiff to show both "but for" causation and proximate causation. See, e.g., Holmes, 503 U.S. at 265-68. The essence of Plaintiff's allegations is that the § 1962(c) RICO scheme (defrauding Colorado annuity customers) caused his injuries (termination from Allianz, the loss of his insurance license, and the loss of his income) because Defendants would never have had reason to sacrifice him to the DOI [the Colorado Division of Insurance] unless they needed to cover up their unlawful racketeering activities.... Although these allegations establish a "but for" causal connection between the scheme and the injuries, proximate causation requires more. See, e.g., Gregory P. Joseph, Civil RICO: A Definitive Guide 31 (1992) ("Legal liability does not extend as far as factual causation."). There must be some "'direct relation between the injury asserted and the injurious conduct alleged.'" Anza v. Ideal Steel Supply Corp., 547 U.S. 451, 457, 126 S. Ct. 1991, 164 L. Ed. 2d 720 (2006) (quoting Holmes, 503 U.S. at 268). In imposing a proximate cause requirement on RICO plaintiffs, the Supreme Court recognized that it would, in effect, "limit a [RICO defendant's] responsibility for the consequences of that person's own acts." Holmes, 503 U.S. at 268. Such a requirement was acceptable, however, for reasons of administrative necessity. "[T]he less direct an injury is, the more difficult it becomes to ascertain the amount of a plaintiff's damages attributable to the violation, as distinct from other, independent factors." Id. at 269. Further, without a proximate cause requirement, courts would be forced to "adopt complicated rules apportioning damages among plaintiffs removed at different levels of injury from the violative acts, to obviate the risk of multiple recoveries." Id. And finally, the Court noted that a proximate cause requirement would not absolve RICO violators of their wrongs "since directly injured victims can generally be counted on to vindicate the law as private attorneys general, without any of the problems attendant upon suits by plaintiffs injured more remotely." Id. at 269-70.