The rapid advancement of algorithmic trading has demonstrated the success of AI automation, as well as gaps in our understanding of the implications of this technology proliferation. We explore ethical issues in the context of autonomous trading agents, both to address problems in this domain and as a case study for regulating autonomous agents more generally. We argue that increasingly competent trading agents will be capable of initiative at wider levels, necessitating clarification of ethical and legal boundaries, and corresponding development (...) of norms and enforcement capability. (shrink)