This study develops a network-level model of banking alliances by integrating neo-institutional isomorphism and tie strength theory. Based on an integrative review of 98 empirical studies and deductive–inductive content analysis, the model explains how institutional pressures and relational mechanisms shape alliance portfolios among interconnected banking actors. The analysis identifies recurring patterns: strong-tie alliances, such as mergers and acquisitions and joint ventures, appear more often under high coercive and normative isomorphism, whereas moderately and loosely coupled alliances, including information sharing and outsourcing, are more common where institutional alignment is weaker and uncertainty is higher.
