Venture accelerators provide essential professional training and entrepreneurial resources that are critical to the growth of social enterprises. To attract the attention of accelerators, social enterprises must effectively employ signaling mechanisms to convey their unique advantages. Drawing upon signaling theory and the literature on social entrepreneurship, this study conducts an empirical analysis based on a unique dataset of 11 369 social enterprises from the Global Accelerator Learning Initiative (GALI) from 2016 to 2019. The findings reveal that founders’ capital investment serves as a key signal that increases the likelihood of a social enterprise being selected by an accelerator. Further analysis shows that a single-founder structure and the possession of patents strengthen the signaling effect, whereas the level of internationalization in the enterprise’s home country can partially substitute for the signal of founder capital investment. This research not only deepens our understanding of social enterprise financing mechanisms and fills the gap in studies on accelerator selection, but also enriches the analytical framework of signaling theory from a multi-source signal fitting perspective, offering valuable theoretical and practical implications for both social enterprises seeking resources and accelerators making selection decisions.