Comparing case studies of long-term, large-scale urban regeneration projects in Glasgow and Edinburgh, Scotland, this paper brings together two addendums to the rent gap model in the shape of the ‘reputational gap’ and the ‘state subsidy gap’. These neologisms are mobilised to clarify the risk-laden centrality of the state’s role in both the formation and potential closure of rent gaps in large-scale areas of disinvestment and devalorisation. Whilst such projects often appear as expressions of capital’s state-mediated extractive power over the built environment, we consider them as examples of capitalist failure or fragility – for even with striking levels of public subsidy to address ‘market failure’ the land and property market has not been reinvigorated according to plan. This highlights the need, we argue, for further critical scrutiny of failed or stalled urban regeneration projects as a means of foregrounding the instability, rather than the omnipotence, of contemporary urban capitalism.