The merged group will be known as Janus Henderson Global Investors plc and is expected to complete in the second quarter of 2017, subject to shareholder and regulatory approvals, a London stock exchange statement stated on Monday.
The merger will be effected via a share exchange with each share of Janus common stock exchanged for 4.7190 newly issued shares in Henderson.
Henderson and Janus shareholders are expected to own approximately 57% and 43% respectively of Janus Henderson Global Investors' shares on completion.
Andrew Formica, chief executive of Henderson, said "Henderson and Janus are well-aligned in terms of strategy, business mix and most importantly a culture of serving our clients by focusing on independent, active asset management. I look forward to working side-by-side with Dick, as we create a company with the scale to serve more clients globally, as well as the strength to meet their future needs and the growing demands of our industry."
Dick Weil, chief executive officer of Janus, said: "This is a transformational combination for both organizations. Janus brings a strong platform in the US and Japanese markets, which is complemented by Henderson's strength in the UK and European markets. The complementary nature of the two firms will facilitate a smooth integration and create an organization with an expanded client-facing team and product suite, greater financial strength, and enhanced talent, benefiting clients, shareholders and employees."