The case describes Aviva Investors' engagement strategy with companies and stock exchanges to improve its sustainability performance and the flow of sustainability related information to markets. Aviva Investors, a GBP 259 billion fund, is the investment arm of the large British insurance company, Aviva plc. Aviva Investors is committed to sustainability under the leadership of its CEO, Paul Abberley, and head of sustainability research and engagement, Steve Waygood. The case describes Aviva Investors' policies on materiality, engagement, and its corporate responsibility voting policy. It then explores how the company is implementing these policies in the case of a particular company, the FTSE 100 diversified mining company Vendanta, and the Sustainable Stock Exchange Initiative under the sponsorship of the UN Principles for Responsible Investment.