**U.S. nuclear test probabilities remain low as traders price in sustained U.S. restraint despite earlier signals.** President Trump’s October 2025 directive to resume testing “on an equal basis” with Russia and China prompted initial market movement, but subsequent clarifications from Energy Department officials ruled out nuclear explosive detonations in favor of sub-critical or non-nuclear experiments. The most recent development—a September 2026 NNSA chemical high-explosive test at the Nevada National Security Site—focused on refining detection algorithms for low-yield or decoupled foreign blasts rather than advancing U.S. explosive testing. Stockpile stewardship programs continue to affirm no technical requirement for full-yield tests, with any potential resumption framed as a multi-year planning exercise rather than an imminent step. Upcoming diplomatic or verification talks could further shape timelines, but current consensus reflects the absence of confirmed preparations for a nuclear chain-reaction detonation.