Important information: To clarify, the U.S.–Iran memorandum of understanding reportedly now in effect does not satisfy criterion (1) of the definition of a "new Iran-US nuclear deal," and this market will therefore not resolve to Yes on the basis of that instrument at this time.
The memorandum provides for the existing state of Iran's nuclear program to be maintained pending a subsequent agreement, and defers the disposition of Iran's stockpile of enriched uranium to a mechanism to be mutually agreed in that subsequent agreement. That it states a minimum methodology for that future mechanism — down-blending on site under IAEA supervision — constrains the form of a mechanism yet to be agreed, but specifies no quantity, enrichment level, or completion deadline for the down-blending. An instrument that provides for maintaining Iran's nuclear program at an unspecified status quo, or that defers its substantive nuclear commitments to a subsequent agreement, does not by itself establish the concrete, objectively ascertainable standard that a "verifiable" restriction requires.

An agreement also made with other countries (i.e. multilaterally) is still encompassed if the United States participates. "A new Iran-US nuclear deal" means a formal written agreement signed by authorized representatives of both the United States and Iran that (1) imposes verifiable restrictions on Iran's nuclear program, including limits on uranium enrichment, centrifuge numbers, or nuclear facility operations, AND (2) provides for the lifting, suspension, or modification of at least one US economic sanction on Iran in exchange for Iran's nuclear commitments.
Clarification (04/19/26): The Agreement Long rulebook variable defines the nature of the qualifying instrument: it must be a formal written agreement signed by authorized representatives of both governments. It does not impose a precondition that the signing itself must occur before resolution. Because the Payout Criterion is satisfied if the United States has "agreed to, signed, or accepted" such an instrument, both governments publicly and officially agreeing to the terms of what will be a qualifying written agreement is sufficient to resolve the market to Yes, even if the formal signing has not yet taken place.
Clarification (06/02/26): A qualifying instrument must impose "verifiable restrictions on Iran's nuclear program." A restriction is "verifiable" only where it establishes a concrete, objectively ascertainable standard (a defined limit, prohibition, quantity, or monitoring provision) against which compliance could in principle be confirmed; a general expression of intent that fixes no such standard is not considered “verifiable” for the purposes of this event. Accordingly, a bare pledge not to develop or pursue nuclear weapons, unaccompanied by any concrete limit on Iran's nuclear materials, activities, or facilities, does not on its own satisfy criterion (1). Conversely, a commitment to completely 'stop' or ‘suspend’ a specific nuclear activity (such as uranium enrichment) establishes a concrete prohibition (an implicit limit of zero) and qualifies as a restriction, whereas a vague promise to 'reduce' activities without a defined metric or monitoring mechanism does not. The enumerated examples (limits on uranium enrichment, centrifuge numbers, or nuclear facility operations) are illustrative and not exhaustive: a formal, verifiable commitment to remove, transfer, or cap Iran's stock of enriched uranium, confirmable by the receiving state or an oversight body, is a restriction on Iran's nuclear program and satisfies criterion (1). In every case, criterion (2) must independently be met.