Anthropic’s June 9, 2026 release of the public Claude Fable 5 and restricted Claude Mythos 5 established the current three-to-five-month cadence traders use to price the next Mythos-class model. Recent expansion of Mythos 5 access to additional cybersecurity partners and a new $35 million open-source defender fund signal continued focus on controlled rollout rather than immediate broad availability. No official announcements or credible leaks have emerged since late June, leaving sentiment anchored to historical timing, safety evaluations, and compute priorities amid ongoing U.S. government oversight of high-capability cybersecurity features. Markets currently cluster expected text-arena or public debut probabilities in early-to-mid September, with resolution hinging on whether Anthropic clears internal safeguards and regulatory checks before the end of the month.