The transportation end-use industry is the fastest-growing segment of the polyetherimide (PEI) market. In terms of volume, the transportation end-use industry is estimated to lead the PEI market, while the electrical & electronics segment is estimated to account for the second-largest share of the global polyetherimide (PEI) market. The use of PEI has been increasing due to its ability to replace metal and other thermosets and bulk molding compounds. PEI is apt for applications that require high heat resistance, strength, and chemical resistance. The largest application of PEI is in the electrical and lighting systems, followed by under-the-hood applications. Reinforced PEI is formulated to meet the various engineering demands. It can be categorized into two types, namely, glass reinforced and fiber reinforced. Glass reinforced PEI provides greater dimensional stability and improved electrical and mechanical properties while retaining excellent processibility.