The article talks about a new theory in business law called principal-cost theory. It's different from the usual agency-cost theory that focuses on reducing manager's control. This new theory says that businesses choose governance structures to minimize the costs of investors making decisions (principal costs) and managers running things (agent costs). Each company picks the best structure based on these costs, which vary for different firms. Unlike the old theory, this new one gives better predictions based on real data. It suggests that laws should allow companies to customize their governance structures instead of forcing one-size-fits-all rules.