This study explores individual and country-level environmental drivers of informal “seed” investment. We examine four types of informal investors based on business ownership experience (or no such experience) and close family relationship with investee (or no such relationship): “classic love money”, “outsider”, “kin owner” and “classic business angel” investors. At the environmental level, we are interested in the role of economic development, income tax policies, start-up costs, pro-enterprise government programmes, availability of debt financing, entrepreneurship education and culture. Using Global Entrepreneurship Monitor data from telephone interiews with 257,793 individuals in 31 countries, including 5,960 informal investors, we report drivers for the four types of seed investment. Descriptive statistics are consistent with prior research: informal investors are likely to be older males who work full-time, earn high incomes, perceive start-up opportunities in the environment, and believe that they have the skills to start their own businesses. At the environmental level, we find that countries with higher percentages of informal investors are significantly likely to have higher levels of economic development, higher business start-up costs, higher levels of entrepreneurship education, lower income taxes and lower power distance. Other environmental effects on the four populations of informal investors are reported and discussed, as well as implications for practice, policy and future research.