Janus Henderson Group plc Acquires 9.99% Passive Stake in Cellectar Biosciences, Inc.

On June 5, 2026, Janus Henderson Group plc filed a Schedule 13G disclosing a new 9.99% passive ownership stake in Cellectar Biosciences, Inc. (CLRB). The filing indicates that Janus Henderson Group plc, acting as the ultimate parent company for various SEC-registered investment advisers, beneficially owns 798,382 shares of common stock. The reporting person also disclosed substantial derivative holdings, including 1,051,520 pre-funded warrants and several series of additional warrants (Series A, B, and C, each totaling 1,886,792). However, these warrants are subject to a blocker provision preventing exercise if it would result in ownership exceeding the 9.99% threshold. The shares were acquired in the ordinary course of business, with shared voting and dispositive power attributed to the managed portfolios. Specifically, the Janus Henderson Biotech Innovation Master Fund Ltd. was identified as having the right to receive dividends or sale proceeds from more than 5% of the issuer's common stock. This filing marks a significant new institutional position in the biopharmaceutical company.