UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 for the transition period from to Commission File Number 001-38103 JANUS HENDERSON GROUP PLC 98-1376360 (I.R.S. Employer Identification No.) EC2M3AE (Zip Code) +44 (0) 20 7818 1818 (Registrant's telep ...