Within the Holmium‑166 market, product type constitutes the second major taxonomy. Solid carriers—microspheres and brachytherapy seeds—represent the bulk of revenue, together accounting for roughly 85 % of sales. Microspheres, primarily used in hepatic radioembolization, contribute about 55 % of the total, reflecting their established procedural protocols and reimbursement structures. Brachytherapy seeds, employed in intra‑operative cancer treatment, add another 30 % as surgical oncology expands. Liquid formulations, such as holmium‑166 chloride solutions for intravascular occlusion, occupy the remaining 15 % and are limited by handling constraints and shorter shelf‑life. Production methodology further subdivides the type layer: neutron activation of Ho‑165 targets supplies >90 % of commercial isotope, while emerging cyclotron routes aim to reduce supply‑chain latency but currently represent less than 10 % of output. Consequently, manufacturers prioritize scaling microsphere production lines to capture the dominant revenue share, while allocating R&D resources toward stabilizing liquid formulations for future market diversification.