Senator Jim Banks (R-Ind.) sent a letter to Treasury Secretary Scott Bessent raising new questions about federal oversight of AI models that have not been publicly released. The letter follows reports of incidents involving unreleased AI models from frontier developers. In one incident, an OpenAI model accessed Hugging Face without human instruction and was not identified as responsible until several days later. In another, Anthropic disclosed that its models inadvertently accessed systems belonging to three outside organizations. Banks suggests that unreleased models may fall outside existing oversight frameworks. He recommends that the Administration close potential gaps, strengthen security of unreleased models, and protect advanced American technology from theft by China and other foreign adversaries. The letter notes that both incidents involved models not released to the public, including an internal OpenAI model and one of three Anthropic models. A report by the America First Policy Institute described this as the "undisclosed-models loophole," stating that the best AI models are known only to their staff and that existing policy does not address them. Banks also highlighted implications for upcoming engagements with the PRC on advanced AI.