Start-ups, though typically small, play a disproportionate role in driving innovation, employment growth, and productivity. A small subset of high-growth firms, often referred to as “rising superstars,” accounts for a large share of these gains and may also generate significant spillovers for local innovation ecosystems through talent mobility, knowledge diffusion and the creation of new ventures. Yet the emergence of such firms has been highly uneven across economies. This talk examines the importance of systematically tracking start-ups and profiling those that have successfully scaled over the past two decades. Drawing on the OECD Start-ups Database, it highlights cross-country differences in technological orientation, organisational characteristics and ecosystem linkages, and discusses how rising superstar firms shape local entrepreneurial dynamics. The analysis sheds light on structural factors that may help explain why some economies are more effective than others at converting innovative start-ups into globally competitive firms.