Judge Posner authored a unanimous opinion at the close of 2010 holding that a denial of a Rule 12(b)(6) motion to dismiss based on Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007), raised a “controlling question of law” suitable for interlocutory appeal pursuant to 28 U.S.C. § 1292(b). In re Text Messaging Antitrust Litigation, 630 F.3d 622 (7th Cir. 2010) (based largely on the uncertainty surrounding the Twombly legal standard). The court then held that the district court had properly denied the motion to dismiss based on Twombly.

Text Messaging concerned consolidated class action proceedings accusing defendants of conspiring to fix prices for text messaging services. The district court denied a Twombly motion to dismiss and certified its ruling, at defendants’ request, for interlocutory appeal, stating that the application of Twombly remained unclear; that reasonable minds could differ on its application here; that the question was controlling because granting the motion to dismiss could terminate the case; and that immediate review would materially advance the ultimate conclusion of the case. Plaintiffs opposed certification for appeal in the district court, asserting that no controlling question of law was involved, and then asked the court of appeals to refuse the required permission for an interlocutory appeal.