The paper provides a taxonomy of group speech acts whose main division is that between collective speech acts (singing Happy Birthday, agreeing to meet) and group proxy speech acts in which a group, such as a corporation, employs a proxy, such as a spokesperson, to convey its official position. The paper provides an analysis of group proxy speech acts using tools developed more generally for analyzing institutional agency, particularly the concepts of shared intention, proxy agent, status role, status function, convention and constitutive rule.