Traders are watching Anthropic’s rapid 5-series cadence and stable per-token economics after Claude Opus 5.5 launched September 22 at the same $5/$25 per million input/output rate as Opus 5. Early October reports of silent routing from Opus 5.5 to an unidentified newer model fueled speculation around an imminent 5.6, yet Anthropic has issued no model ID, benchmarks, or pricing details as of mid-October. Historical patterns show output-token pricing held steady across recent Opus upgrades despite competitive pressure from lower-cost alternatives like GPT-5.6. Key near-term catalysts include any official 5.6 announcement, API rate-card updates, or developer-conference commentary that could signal a shift in output pricing structure.