Most of the current literature on academic spin-offs is concerned with what determines the emergence of spinoffs, with few studies tackling the crucial academic and policy question of whether (and which) spin-offs actually grow (Djokovic and Souitaris 2004). The heterogeneity in the nature of research-based spin-offs across Europe adds to the complexity of the issue.

Therefore, we attempt to answer the question “What determines the capital invested in and subsequently the growth of research-based spinoffs?” focusing on the relative effect of two types of variables:

- “Nurture” variables which describe the resource interaction between the research institution and the spinoff firm at the start-up phase. Our three selected nurture variables are 1) the type of incubation model of the research institution (adopted from Clarysse et al. 2005), 2) the formal (versus informal) transfer of technology through assignment of a patent or license at time of founding and 3) the extent of inventor’s involvement with the company (we test the trichotomous taxonomy developed by Nicolaou and Birley 2003).

- “Nature” variables ‘describe’ the company’s type of business. Our two selected nature variables are 1) the technology domain and 2) the complexity of the sales process.