The objective of this article is to assess and compare the factors influencing the performance of new ventures within top business accelerators across three countries using the Resource Based View (RBV) theory. Research Design & Methods: The key analysed parameters are funding dimensions, survivability, acquisition, and growth of 1286 new ventures that graduated from the top two accelerators in Brazil, India, and the USA, i.e. countries from developed and emerging economies. Methods we used were machine learning and two independent sample t-tests. Findings: Input seed funding by accelerators played a dominant role and improved funding trajectories. The external ecosystem was an important differentiator and impacted new ventures' survivability, growth, and funding outcomes. Capabilities and competencies of accelerators differentiated outcomes within the same ecosystem while external environment dampened accelerator outcomes in emerging economies. Implications & Recommendations: Accelerators from emerging ecosystems should strive to augment their human capital and network capabilities, including seed funding, while policy-makers should improve ecosystem index values mentioned in this study. Contribution & Value Added: This is the first of its kind study that extended the RBV theory to accelerators and disentangled the effect of the external environment and RBV on accelerators across three ecosystems with a comprehensive framework of measures. It provides value to practitioners in India and Brazil by highlighting lacunae in their accelerator programs and possible approaches to address them successfully. Article type: research article