Opinion of the Court
into Section 18041, the Act tells the Secretary to "establish and operate such 'American Health Benefit Exchange established under section 18031.'" That suggests that Section 18041 authorizes the Secretary to establish an Exchange under Section 18031, not (or not only) under Section 18041. Otherwise, the Federal Exchange, by definition, would not be an “Exchange” at all. See Halbig, 758 F. 3d, at 399–400 (acknowledging that the Secretary establishes Federal Exchanges under Section 18031).
This interpretation of "under [42 U. S. C. §18031]" fits best with the statutory context. All of the requirements that an Exchange must meet are in Section 18031, so it is sensible to regard all Exchanges as established under that provision. In addition, every time the Act uses the word "Exchange," the definitional provision requires that we substitute the phrase “Exchange established under section 18031." If Federal Exchanges were not established under Section 18031, therefore, literally none of the Act’s requirements would apply to them. Finally, the Act repeatedly uses the phrase “established under [42 U. S. C. §18031]” in situations where it would make no sense to distinguish between State and Federal Exchanges. See, e.g., 26 U. S. C. §125(f)(3)(A) (2012 ed., Supp. I) ("The term 'qualified benefit' shall not include any qualified health plan . . . offered through an Exchange established under [42 U. S. C. §18031]"); 26 U. S. C. §6055(b)(1)(B)(iii)(I)(2012 ed.) (requiring insurers to report whether each insurance plan they provided "is a qualified health plan offered through an Exchange established under [42 U. S. C. §18031]"). A Federal Exchange may therefore be considered one established "under [42 U. S. C. §18031]."
The upshot of all this is that the phrase "an Exchange established by the State under [42 U. S. C. §18031]" is properly viewed as ambiguous. The phrase may be limited in its reach to State Exchanges. But it is also possible that the phrase refers to all Exchanges—both State and
