This study analyzes the intricate dynamics of cross-border interfirm interactions in the working capital financing of small and medium-sized enterprises (SMEs) by using a novel cyber-behavioral signaling perspective. It emphasizes the pivotal role played by the generation and transmission of credible signals to mitigate informational disparities inherent in SME finance. While extant literature predominantly focuses on physical-centric signal types, our work sheds light on SMEs’ strategic use of behavioral factors in the network ecology to generate and transmit signals. Grounded in signaling theory and informed by network ecology, we propose that network ecology constitutes a fertile environment for SMEs to effectively communicate their creditworthiness through high-quality signals. Using survey data from 276 Chinese SMEs, our empirical analysis reveals that cross-border interfirm effects—both unintentional network spillover and intentional network transitivity—significantly bolster SME financing outcomes. Leveraging digital knowledge repositories mediates the strength and effectiveness of these signals, and exerts an even stronger positive impact on SME working capital financing in the absence of well-established normative mechanisms in the wider business ecosystem. By integrating a cyber-behavioral dimension into signaling theory within the SME financing domain, this research offers new understanding on how SMEs can harness the untapped power of their interconnected relationships to secure external capital. The study contributes to theory and practice by elucidating pathways for SMEs to navigate complex interfirm linkages to facilitate improved access to working capital.