Whether to share the ownership of a new venture and how to structure that shared property are decisions commonly faced by founders that have important consequences for start-ups. Yet, how founders make these decisions remains somewhat unattended to in the literature. Through an in depth exploratory study, this paper contributes a textured understanding of how founders deal with the aforementioned decisions. More specifically, this study places its research focus on the behavior of founders to build theory to contribute an answer to the following questions: After having an idea and seizing an opportunity, how do founders decide whether to share the property of their ventures and how to structure it? What guiding criteria orient them? How do these decisions evolve over time? How do founders, in making these decisions, come to embrace their role as owners of a nascent firm?