Segmentation by type classifies biologic agents according to their molecular target, a taxonomy that shapes competitive positioning and pipeline development. TNF‑α inhibitors (e.g., etanercept, adalimumab) remain a substantial legacy cohort, sustaining roughly 35 % of total sales despite emerging alternatives. IL‑17 inhibitors (secukinumab, ixekizumab) have captured approximately 25 % of the market, driven by rapid onset and high skin‑clearance rates. IL‑23 inhibitors (guselkumab, risankizumab) are the fastest‑growing segment, currently representing 30 % of revenues, reflecting strong efficacy in both plaque psoriasis and psoriatic arthritis. IL‑12/23 inhibitors (ustekinumab) hold a smaller, yet stable, 8 % share, while emerging bispecific antibodies and next‑generation small‑molecule biologics collectively account for the remaining 2 %. This type‑based taxonomy clarifies how mechanistic differentiation translates into distinct market shares, informs pricing power, and guides R&D investment priorities.