Unfilled polycarbonate in primary forms is classified as a polycarbonate resin, but compounded grades containing glass fiber, flame retardants, or other fillers may be reclassified as mixtures or compounds under a different HTS heading depending on the nature and proportion of the additives. A technical data sheet showing the compound composition is essential for accurate entry.

Global PC resin production is concentrated among a small number of integrated producers, making supply availability sensitive to plant outages and feedstock (bisphenol A and phosgene) disruptions. Section 301 tariffs on Chinese-origin PC have led some US buyers to qualify alternative sources in South Korea, Germany, and Thailand, though lead times and minimum order quantities differ significantly across regions.