This study examines a disruption in Private Equity (PE) syndication characterized by the increasing role of non-PE firms (outsiders), such as banks and corporates, in syndicated deals. Given the limited theoretical and empirical foundation surrounding this phenomenon, we adopt an exploratory approach that combines machine-learning-enabled pattern discovery with theory development and theory testing. This approach uncovers robust patterns in a comprehensive sample of PE deals that illuminate two distinct pathways through which banks and corporations influence the likelihood of multiple PE firms co-participating in syndicated deals. Building on these detected patterns, we develop a plausible theoretical explanation for these pathways. First, banks, governed by stringent disclosure standards, enhance governance by mitigating information asymmetries, thereby increasing the likelihood of PE-PE syndication. Second, corporations, due to their extensive operational involvement—particularly in exploratory PE deals—introduce resource-related complexities that may deter multiple PE firms from participating in a syndicated deal. Finally, we rigorously test the validity of our explanation through comprehensive mechanism tests. To do so, we employ robust econometric specifications on an independent holdout sample distinct from that used for pattern detection—the distinct samples ensure that findings are not due to sample-specific idiosyncrasies. These findings provide a nuanced understanding of the changing PE syndication dynamics and offer broader implications for multi-party alliances involving industry outsiders, both from governance and resource-based perspectives.