We continued to implement a more detailed ESG scoring system for our corporate issuers. We have a specific module within our Credit Research database that explicitly links the ESG rating each analyst assigns an issuer to the broader forward credit rating that issuer will receive, ensuring that ESG considerations are explicitly considered and weighted in AB's proprietary overall forward rating for each issuer. In this way, our ESG scores have a direct influence on security selection decisions within our portfolios.
In December 2018, we launched a centralized ESG research tool that provides a standard ESG materiality framework and is used to capture ESG research and engagements across our Equities business unit globally. The tool will also capture our fixed income analysts’ research views, and these analysts will have access to the tool so we are able to share ESG viewpoints and engagements across asset classes.
During 2018, we also continued to expand our efforts in impact and sustainable thematic investments.
We have managed a US Municipal Impact strategy since 2016, and continued to expand this strategy during 2018 to a broader range of clients and investment platforms, with assets now totalling over USD 400 million. The US municipal bond market is ripe with opportunities to invest in underserved communities and have social/environmental impact. It also allows us to meet the growing demand from our diverse client base and to provide investment strategies that deliver not only return, but also social/environmental benefits. Our US Municipal Impact strategy also provides ample opportunity to engage with issuers on ESG concerns. During 2018, we engaged on health issues, particularly the opioid crisis, and issues involving access to healthcare in underserved rural areas. We also engaged in collaboration with other organizations on juvenile justice reform.
Our Impact strategy has an established investment structure in which municipal research analysts-in addition to their traditional fundamental analysis-score each issuer on Environmental, Social and Governance criteria. Bonds with an "impact score" below a certain threshold are not eligible for investment in the Municipal Impact Strategy.
Additionally, to meet the growing global investor interest in sustainability, we have developed a Sustainable Global Thematic Credit Strategy. The strategy- expected to be seeded in the first half of 2019 - invests in fixed income issuers whose businesses are aligned with the United Nations Sustainable Development Goals.
We also utilize ESG screening within portfolios, primarily at our clients' direction as described later in this document.