Janus Capital Group Inc. and Henderson Group Plc proposed to pay a first-quarter dividend to their respective shareholders before the completion of their merger.

Henderson Group said its payout will be an extraordinary dividend of "commensurate value" to the dividend paid for shareholders of Janus Capital and is being made "with a view to ensuring equality of treatment of Janus and Henderson shareholders."

The amount and payment date of the extraordinary dividend will be announced April 19. Henderson Group's final dividend for full year 2016 will be announced alongside its results Feb. 9.

The companies' proposed dividends are subject to approval by their respective boards.