During industry emergence, what is called the proto-industry phase, the lack of agreement about legitimate organizational forms between audiences and firms is a key problem. The authors develop an ecological model of emerging institutional pressures among audiences and firms during the emergence of new industries to understand these challenges. They develop a theoretical framework that includes mimetic, normative, and coercive pressures, deriving propositions linking them with survival and growth. The authors use simulation methodology to test these propositions, finding strong support for these predictions. They close by exploring some conclusions and implications of our model for both theory and practice.