Applying constraints in ESG portfolio optimization:

In quantitative ESG portfolio optimization, constraints are formulated mathematically asupper and lower boundson selected variables (e.g., maximum portfolio carbon intensity, minimum ESG score floor). These constraints are integrated into the optimization model—typically via mean‑variance frameworks that include ESG risk metrics—to ensure portfolios meet predefined ESG thresholds. Whileexclusionary screening(option A) is a form of constraint before optimization, it is not in itself the definition of constraints within the optimization model. Additionally, ESG optimization is not limited to carbon metrics (contrary to option B), as data availability now supports multiple ESG indicators. The precise procedure is to constrain each ESG-related characteristic to a specified range during optimization.