The type‑based market taxonomy of General Purpose Grade Polymethyl Methacrylate distinguishes four core product forms that shape production planning and pricing dynamics. Sheet is the dominant form, supplied in thicknesses from 0.5 mm to 25 mm, and supports most application categories because it can be easily cut, drilled and thermo‑formed; its versatility translates into the largest revenue proportion. Rods, typically 10 mm to 150 mm in diameter, serve machining‑intensive uses such as precision lenses and custom optical components, contributing a modest but stable share. Extruded profiles—long, continuous sections with predefined cross‑sections—are favored in signage and architectural framing where consistent geometry reduces secondary processing costs. Cast PMMA, produced by bulk polymerization in molds, delivers superior optical homogeneity and is preferred for high‑performance optical lenses and medical devices, albeit at a higher unit cost and lower volume. Emerging custom‑fabricated solutions, which combine machining, coating and assembly, are gaining traction in niche markets, incrementally expanding the overall market size without altering the primary segment hierarchy.