Universities' fundamental missions generally differ. For example, institutions can either focus on research or on teaching. Over time, these missions tend to change, and in some cases this is referred to as "mission creep". This negative epithet is reserved for universities with limited research capacities that try to emulate research-intensive universities. In most cases, it appears to be driven by the desire to improve their position in league tables. This paper studies mission development within three different university systems (in England, New York State and California) from a resource-dependency perspective. It focuses in particular on the mission development of comprehensive four-year universities within those systems. The analysis shows that although some emulation of research-intensive universities can be observed, there is a dominant drive to build a unique brand that cannot be equated with the profile of a research-intensive institution. The paper concludes with some general observations on mission development and the need for further research.