OpenAI cuts GPT-5.6 Luna to $0.20 per million input tokens as Chinese models undercut mid-tier pricing

OpenAI and Anthropic executed targeted price reductions on mid-tier models in August 2026. OpenAI applied an 80 percent cut to GPT-5.6 Luna. Anthropic released Opus 5 at $5 input and $25 output per million tokens and canceled the scheduled Sonnet 5 increase. Both actions align with documented benchmark gaps against Moonshot Kimi K3 and DeepSeek V4 Flash. Artificial Analysis data show Opus 5 at medium effort matches Kimi K3 at max effort on task cost while GPT-5.6 Luna at max effort costs nearly twice as much as DeepSeek V4 Flash at equivalent performance. Token-price comparisons alone fail to capture these outcomes because effort settings and token efficiency alter real expenditure. US labs are protecting flagship model margins while compressing mid-tier offerings. Chinese entrants have captured cost-sensitive workloads through lower headline rates and competitive task throughput. This pattern mirrors prior semiconductor and cloud price cycles where second-tier suppliers forced margin compression on non-premium segments. Sustained differentiation now depends on verifiable task-completion economics rather than list prices. Providers that cannot demonstrate lower total cost per solved problem risk share loss in developer and enterprise budgets within the next two quarters.