OpenAI expanded its ecosystem in January 2024 with the launch of its new transformative GPT Store (Store) that allows subscribers to use and share custom chatbots. The standalone GPTs in the Store have capabilities for tasks like booking flights, summarizing a collection of PDFs or assisting negotiations – extending beyond the pre-loaded ChatGPT and DALL-E functions. In three months, the Store has attracted three million GPTs. This article examines the top security issues, including sizable third-party perils, of the Store and identifies key priorities for compliance professionals and company engineers for mitigating the risks of the new GPT app marketplace. It also suggests resources for cyber compliance professionals to monitor security concerns around large language models. See “Dos and Don’ts for Employee Use of Generative AI” (Dec. 6, 2023).