The International Code of Marketing of Breast-milk Substitutes and subsequent resolutions (the Code) was adopted to address increases in mortality and morbidity resulting from the practices of the breast-milk substitute (BMS) industry. The lack of success in ensuring company compliance with the Code has prompted advocates to consider engaging with investors to shape the governance of BMS companies. To support these efforts, this paper aimed to identify prominent investors in the global BMS industry and explore their Code-related policies and practices. Using multiple methods and data sources, we developed a novel approach to identify and rank investors in the world's leading publicly listed BMS companies. We also examined the policies and voting behaviour of a sample of investors using publicly accessible materials from 2020 to 2022. We found that a small number of large investors, led by BlackRock and Vanguard, hold a substantial share in the global BMS industry. Of the top-10 ranked investors, only Norway's Government Pension Fund (NBIM) reported policy information relating specifically to BMS marketing. Most of these large investors also opposed the sample of public health-related shareholder proposals analysed. In addition, we identified several investors that have reported engaging with BMS companies on Code-related issues, including NBIM, Pictet, and UBS, along with several potential investor targets for future advocacy efforts, including some North American public pension funds. The inclusion of Code-related issues as part of broader policies, disclosures and regulations related to environmental, social and governance oriented investment warrants increased attention.