Within the market taxonomy, types of Residue Upgrading Catalysts are classified by composition and functional architecture, each influencing total market size through distinct performance attributes. Metal‑based catalysts (e.g., Ni‑Mo, Co‑Mo sulfides) dominate the hydrotreating niche because of their proven activity for desulfurization, contributing a substantial portion of catalyst revenue. Zeolite catalysts provide shape‑selective cracking ability essential for FCC units, and their high thermal stability secures a sizable market share. Acidic catalysts, such as amorphous silica‑alumina, are employed in coking and certain hydrocracking routes, offering cost‑effective acidity but limited longevity, thus occupying a moderate market slice. Bifunctional catalysts combine metallic sites with acidic frameworks to enable simultaneous hydrogenation and cracking, increasingly adopted in integrated residue conversion schemes. Finally, nano‑structured catalysts—including mesoporous and core‑shell designs—are emerging across all applications, driving incremental growth as refineries pursue higher conversion efficiencies and lower catalyst loadings. Together, these types define the competitive landscape and underpin the aggregate market valuation.