Hedge fund managers are increasingly exploring activist strategies, pursuing campaigns against large companies. However, as recent cases (such as the DOJ lawsuit against ValueAct Capital and two of its funds) show, hedge fund managers following activist strategies must see to operational minutiae to maintain compliance with regulations, filing requirements and various exemptions therefrom. Davis Polk & Wardwell recently presented an overview of the trends, tactics and prospects for shareholder activism and engagement in the U.S., the U.K. and Hong Kong. This first article in a two-part series summarizes the panelists’ insights on the global market for activist investing, how companies should engage with activists and disclosure obligations of activist investors, including filing obligations under the Hart-Scott-Rodino Act. The second article in the series will discuss timing and settlement of activist campaigns, prospects for activism, trends in shareholder engagement and proxy access. For additional commentary from Davis Polk practitioners, see our two-part coverage of PLI’s “Hot Topics for Hedge Fund Managers” panel: “Cybersecurity and Swaps Regulation” (Nov. 5, 2015); and “Operational Due Diligence and Registered Alternative Funds” (Dec. 10, 2015).