Will Mohammed bin Salman sign a U.S. x Iran deal by July 31?

Prediction markets put the probability at 8%: Will Mohammed bin Salman sign a U.S. x Iran deal by July 31. Currently, markets see this as unlikely (8% YES). Markets cheer U.S.-Iran agreement, but some investors caution deal is yet to be signed.

What’s Happening

The probability that Mohammed bin Salman will sign a U.S. x Iran deal by July 31 currently stands at 8%, reflecting deep market skepticism despite a flurry of diplomatic activity. On June 16, 2026, U.S. officials confirmed that a memorandum of understanding outlining the U.S.-Iran deal had been signed electronically by both sides, with a formal signing ceremony expected on Friday, June 19 in Switzerland, to be attended by Vice President JD Vance [CBS News, Tue, Jun 16]. The agreement, which aims to end nearly four months of conflict, has already triggered a 4% drop in oil prices and a rally in Asian stocks, as markets price in the resumption of oil flows through the Strait of Hormuz [CNBC, Mon, Jun 15]. However, the deal’s structure—a preliminary MOU rather than a final treaty—leaves the role of Saudi Arabia ambiguous, as the kingdom has not been a direct party to the U.S.-Iran negotiations.

The core question of whether Mohammed bin Salman will sign a U.S. x Iran deal by July 31 hinges on Riyadh’s strategic calculus. Saudi Arabia, which has been locked in a proxy conflict with Iran in Yemen and the Gulf, has historically demanded that any U.S.-Iran agreement include strict limits on Iran’s ballistic missile program and support for proxies. While the current MOU reportedly focuses on de-escalation in the Strait of Hormuz and a ceasefire, analysts caution that the Saudis may withhold their signature until broader security guarantees are secured, including a commitment from Washington to maintain a military presence in the Gulf [NPR, Wed, Jun 17]. The U.S. Strategic Petroleum Reserve has fallen to its lowest level since 1983, adding urgency for Washington to secure Saudi cooperation to stabilize global oil markets [CNBC, Mon, Jun 15].

The structural factor that will determine whether Mohammed bin Salman will sign a U.S. x Iran deal by July 31 is the timing of the formal signing ceremony and the scope of Saudi demands. Mediators are discussing moving the signing up to as early as Wednesday, June 17, via remote electronic signature, which would immediately implement parts of the deal concerning the Strait of Hormuz [Axios, Wed, Jun 17]. Yet, the Saudis have not publicly endorsed the MOU, and their signature is not required for the U.S.-Iran bilateral deal to take effect. The market’s 92% probability that the deal will not be signed by the Saudi crown prince by the July 31 deadline reflects the view that Riyadh will either delay its endorsement to extract concessions or remain a passive observer, leaving the broader regional architecture unresolved.

Traded on Polymarket — $98K Volume

Lower-volume market on Polymarket ($98K). Wider spreads expected — enter with limit orders and be aware of slippage risk. Currently 10c YES.