Google’s October 13 general availability launch of Gemini 4 Argon, its new frontier large language model optimized for long-horizon agentic coding, complex multi-step reasoning, and enterprise tasks, drives the 72.5% market-implied odds. The model leads key benchmarks including DeepSWE v1.1 at 77.9% and the Vals Index across finance, legal, and coding workloads, outperforming prior Claude releases in early evaluations while offering a 1M-token context window and agentic tooling like Antigravity. Anthropic’s September releases of Claude Opus 5.5 and Fable 5.1 remain competitive on select metrics but lack comparable fresh capability jumps, leaving limited room for those variants to overtake before the October 26 snapshot. Traders are pricing in the recency and demonstrated performance edge of the latest Gemini iteration.