Rep. Mast hints at potential halt to US-Iran conflict within weeks

Rep. Brian Mast, Chairman of the US House Foreign Affairs Committee, suggests a decision to halt the war with Iran may come within weeks. Current odds for a US declaration of war on Iran by December 31, 2026, sit at 7.5% YES, down slightly from 8% a week ago.

Traders are reading Mast’s comments as a de-escalation signal. The December 31, 2026 market holds at 7.5%, showing clear skepticism about a formal war declaration. The April 30, 2026 market is priced at 0.7%.

The term structure shows a 7-point increase from April 30 to December 31, which suggests traders expect potential catalysts later in the year rather than soon. With just 14 days left until April 30, the low odds indicate confidence that immediate escalation is unlikely.

Mast’s remarks also have traders reassessing the likelihood of a US invasion of Iran. The market for an invasion before 2027 hasn’t traded recently, and expectations for such a move are dampened by his de-escalation hint.

Actual USDC volume in these markets is modest: $329 over the past 24 hours, indicating limited conviction. The depth required to move prices 5 percentage points ranges from $1,830 to $2,378, a thin market that could be swayed by larger trades.

Mast’s statement, covered by a tier-2 source, doesn’t guarantee an end to tensions, but it shifts the narrative toward potential congressional action to halt the conflict. At 7.5¢, a YES share pays $1 if war is declared by year-end, a 13.3x return. For that bet to make sense, you’d need to believe current de-escalation efforts will fail.

Watch for upcoming congressional votes and statements from Trump and Secretary of War Pete Hegseth, as these could move market expectations quickly.

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