The Types segment of the Rare Earth Magnet for HDD market distinguishes between two principal alloy families: Neodymium‑Iron‑Boron (NdFeB) and Samarium‑Cobalt (SmCo). NdFeB magnets dominate with an estimated 80 % share, owing to their superior magnetic flux density, cost efficiency, and adaptability to the compact geometries required in modern HDD spindle motors. SmCo magnets, while comprising roughly 20 % of the market, are selected for applications demanding exceptional temperature resilience and corrosion resistance, such as high‑performance enterprise drives operating in harsh environments. Within NdFeB, sub‑grades (e.g., N35, N42, N52) are matched to specific HDD torque and coercivity specifications, enabling manufacturers to balance performance against material cost. SmCo variants (e.g., SmCo5, Sm2Co17) are similarly tiered to address niche reliability criteria. This type‑based taxonomy clarifies how material characteristics allocate value across the Rare Earth Magnet for HDD market, guiding both supplier sourcing strategies and OEM design decisions.