US-Iran Final Nuclear Deal by December 31, 2026?

What this question means

This forecast has been falling steadily, and that is the most informative thing about it.

A month ago the crowd put the chance of a final US-Iran nuclear agreement by the end of 2026 at 26%. It now sits at 10%, having traded as high as 26% and as low as 8% across the tracked period, starting at 23%. That is not noise. That is a sustained repricing in one direction.

Downward drift on a diplomatic question often reflects the calendar as much as the politics. Agreements of this kind take months of negotiation before anything is signed, so as a deadline approaches without a visible framework in place, the probability compresses on its own — there is simply less room left for the process to finish.

Note the word "final". This question is not about talks, interim arrangements, or progress. It asks whether a concluded agreement exists by 31 December 2026, which is a much higher bar than diplomatic activity.