The polytetrahydrofuran (poly THF) market was valued at USD 6.6 billion in 2025, is projected to reach USD 11.8 billion by 2035 and is forecast to register a 6.0% CAGR between 2025 and 2035. In 2025, petro-based poly THF holds 96.2% within the product type segment and spandex fibers represent 68.1% of the application category.