Who is the largest insulation manufacturer in the world?

The largest insulation manufacturer in the world is generally considered to be Owens Corning, headquartered in Toledo, Ohio, USA, when measured by revenue from insulation products and global market share in fiberglass and foam insulation, though the title depends on how you measure and whether you include all insulation types. Owens Corning is the world's largest producer of fiberglass insulation, known for its iconic PINK insulation, and has annual insulation sales of several billion dollars with plants in over 30 countries. Other contenders for largest include Saint-Gobain from France, which owns CertainTeed in North America and Isover in Europe and is massive in insulation and building materials overall with over 40 billion euros in revenue, and Knauf Insulation from Germany, which is one of the largest family-owned insulation makers with strong presence in Europe and North America. Kingspan from Ireland is the largest in rigid foam panels and insulated panels, and Rockwool from Denmark is the largest in stone wool or mineral wool insulation. Johns Manville, owned by Berkshire Hathaway, is also huge in fiberglass and commercial insulation. If you count only fiberglass batts and rolls for residential, Owens Corning is number one in North America and globally. If you count all insulation materials including foam, mineral wool, and panels globally, Saint-Gobain may be larger due to its broader portfolio. Most industry reports list Owens Corning, Saint-Gobain, Knauf, Rockwool, and Kingspan as the top five global insulation manufacturers.