This article explores the ethics of co-writing with large language models such as GPT-4 in professional, non-academic writing contexts without disclosing the practice to stakeholders. It considers five ethical concepts through an analysis of a hypothetical scenario. Three of the concepts—transparency, data practices, and expanded circulation—originate in the work of Heidi McKee and James Porter. The other two, just price and risk imposition, have particular relevance for professional writers. The article ultimately proposes that these five concepts can serve as points of reference as we attempt to formulate and articulate ethical judgments about co-writing with generative AI in specific, contextually grounded instances.