US-Iran nuclear diplomacy centers on the fate of Iran’s pre-strike stockpile of roughly 440 kg of uranium enriched to 60 percent, much of which is believed to remain buried or inaccessible at damaged sites including Isfahan tunnels following 2025 US-Israeli strikes. Iran has refused IAEA inspectors return access and its officials have repeatedly stated that Tehran will neither halt enrichment nor relinquish the material. Recent talks, including a June 2026 memorandum of understanding and subsequent ceasefire extensions, have focused on stockpile disposition, enrichment capacity reductions, and verification, yet no agreement on physical transfer or US possession has emerged. Vice President JD Vance has emphasized the need for “meaningful” cuts to enrichment levels to end the conflict. Traders price low odds of US acquisition by late 2026 because any resolution would require Iranian consent to verifiable removal or downblending under international oversight, amid continued resistance and unresolved verification gaps.