Sustainable debt financing—bonds issued to support projects that benefit the environment or social welfare—has skyrocketed over the past decade, rising from a niche market to a trillion-dollar business. Public finance has been an essential catalyst for the market for sustainable …

The steady growth of sustainable finance in recent years poses difficult questions on how regulators should approach it. In the European Union (EU), for example, there has been an explosion of new rules aimed at addressing a broad array of …