On remand, Panther moved for leave to file the 2PSAC, adding the allegations that Sumitomo Electric and NEC were Ikanos’s two largest customers and that they accounted for 72% of Ikanos’s revenues in 2005. Panther further alleged that, weeks before the Secondary Offering — when Ikanos was receiving an increasing volume of complaints from these customers — Ikanos knew it would be unable to determine which of the chip sets it sold them contained defective chips. In November 2010, the district court denied Panther’s motion, again on the grounds of futility, finding that the 2PSAC failed to allege “ ‘additional facts that Ikanos knew the defect rate was above average before filing the registration statement.’ ” Special App. at 4, 5 (“Panther Partners PV”) (quoting Panther Partners III, 347 Fed.Appx. at 622). Panther’s new allegations regarding Sumitomo Electric and NEC, the district court reasoned,
have no logical connection to the issue of when Ikanos knew that the defect rate was above average. Although these customer demographics might shed light on whether any defect might potentially be problematic assuming the defect rate turned out to be above average, this does not satisfy the Second Circuit’s road map — it is simply a detour.
Id. at 4.
Panther appeals again, arguing that the district court erred by considering in isolation only those allegations in the 2PSAC that supplemented the 1PSAC and by applying the wrong standard in assessing whether the 2PSAC adequately alleged a failure to comply with Item 303. Specifically, Panther argues that the issue before the district court was not whether Ikanos knew the defect rate was “above average” before filing the Registration Statement. Id. at 4, 5 (quotation marks omitted). Rather, the district court should have addressed the question of whether, in failing to disclose the scope of the defect issue with which Ikanos was then grappling, defendants concealed a “known trend[] or uncertainly] ... that [Ikanos] reasonably expect[ed] w[ould] have a material ... unfavorable impact on ... revenues or income from continuing operations,” 17 C.F.R. § 229.303(a)(3)(ii).
STANDARD OF REVIEW
We review a district court’s denial of leave to amend for abuse of discretion, unless the denial was based on an interpretation of law, such as futility, in which case we review the legal conclusion de novo. Starr v. Sony BMG Music Entm’t, 592 F.3d 314, 321 (2d Cir.2010). Futility is a determination, as a matter of law, that proposed amendments would fail to cure prior deficiencies or to state a claim under Rule 12(b)(6) of the Federal Rules of Civil Procedure. See Cortec Indus., Inc. v. Sum Holding L.P., 949 F.2d 42, 50 (2d Cir.1991). In assessing whether the proposed complaint states a claim, we consider “the proposed amendments] ... along with the remainder of the complaint,” Sony BMG, 592 F.3d at 323 n. 3, accept as true all non-eonclusory factual allegations therein, and draw all reasonable inferences in plaintiffs favor to determine whether the allegations plausibly give rise to an entitlement to relief. Iqbal, 556 U.S. at 678-80, 129 S.Ct. 1937.
DISCUSSION
Sections 11 and 12(a)(2) of the Securities Act impose liability on certain participants in a registered securities offering when the registration statement or prospectus contains material misstatements or omissions. 15 U.S.C. §§ 77k, 77l(a)(2). The provisions are “notable both for the limitations on their scope as well as the interrorem nature of the liability they ere-