The short answer is that Twombly has not been adopted by Colorado state courts--at least not at the appellate level, yet. (Of note, a former member of the Colorado Supreme Court was named Twombly, so the name does pop up frequently in Colorado cases in an entirely unrelated context.)
As of March 2012, only one Colorado state appellate court opinion has cited the recent US Supreme Court opinion in Bell Atlantic Corp. v. Twombly, and that case is Western Innovations, Inc. v. Sonitrol Corp., 187 P.3d 1155, 1158 (Colo. App. 2008) (a case on which I was peripherally involved). Sonitrol is anything but an endorsement of Twombly--it is a “but see” cite included as contrast to the quotation of the Colorado pleading standard of complaint should not be dismissed for failure to state a claim unless it appears beyond doubt that the plaintiff cannot prove facts in support of a claim that would entitle it to relief. Coors Brewing Co. v. Floyd, 978 P.2d 663, 665 (Colo. 1999). (Note that Sonitrol was decided before Iqbal, in which the Supreme Court expressly extended the Twombly standard to all federal complaints, not just antitrust matters).
As of March 2012, only one Colorado state appellate court opinion has cited the recent US Supreme Court opinion in Bell Atlantic Corp. v. Twombly, and that case is Western Innovations, Inc. v. Sonitrol Corp., 187 P.3d 1155, 1158 (Colo. App. 2008) (a case on which I was peripherally involved). Sonitrol is anything but an endorsement of Twombly--it is a “but see” cite included as contrast to the quotation of the Colorado pleading standard of complaint should not be dismissed for failure to state a claim unless it appears beyond doubt that the plaintiff cannot prove facts in support of a claim that would entitle it to relief. Coors Brewing Co. v. Floyd, 978 P.2d 663, 665 (Colo. 1999). (Note that Sonitrol was decided before Iqbal, in which the Supreme Court expressly extended the Twombly standard to all federal complaints, not just antitrust matters).
Ultimately, Sonitrol neither adopted nor rejected Twombly. Accordingly, it is uncertain whether Colorado will eventually adopt Twombly. In my opinion, however, it is likely that Colorado will eventually expressly adopt Twombly (or some similar standard). A growing body of case law is developing at the federal level applying Twombly, and the kinks are being gradually worked out. Colorado tends to look on case law interpreting the Federal Rules of Civil Procedure as persuasive precedent in interpreting a similar Colorado Rule. See Benton v. Adams, 56 P.3d 81, 86 (Colo. 2002) ("When a Colorado rule is similar to a Federal Rule," Colorado courts "may look to federal authority for guidance in construing the Colorado rule."). Most importantly, there are several persuasive arguments in favor of the Twombly standard, especially in light of the courts' backlog and the Court's general desire to reduce frivolous litigation.
Already, at the trial court level, Twombly is being used with some success--I have personally referred to Twombly as persuasive authority to support a motion to dismiss, and the motion was granted. While it is certainly not binding precedent at this point, I think courts are both persuaded by the reasoning behind Twombly and its progeny and think it's likely that Colorado appellate courts could adopt some version of Twombly at any time. Accordingly, where possible, I think that courts will look to build a "double hull" into their rulings on motions to dismiss to ensure that they are appropriate under either standard. For the careful practitioner--on both Defense and Plaintiff side--it is important to understand and apply this tension when briefing a motion to dismiss.
Finally, when drafting a complaint in Colorado state court, it is certainly wise to consider Twombly if there is any possibility that the case will be removed to federal court.
-Jeff Vail is a Colorado business litigation attorney at The Law Office of Jeff Vail LLC.