Sustainable investing is an investment approach that considers environmental, social and governance (ESG) criteria in selecting and managing investments. It is now moving away from a niche status to a mainstream consideration. Asset managers face significant challenges in executing their clients’ mandates of sustainable investing. Lack of disclosure, standardization and good-quality data, along with the scarcity of analyst expertise in ESG factor analysis, makes sustainable investing research expensive and time consuming. At the same time, sustainability funds, bonds and ETFs available for investing are limited, making the investment process more complex and time consuming for asset managers. Global sustainable investing AuM more than doubled from 2012-18 to reach USD31tn. – Nevertheless, there is significant headroom for further growth, as sustainable investing assets account for only c. 30% of all professionally managed assets globally. – ESG factors are clearly a key consideration in investing, both for asset managers and asset owners.