Why does transformers oil price vary between manufacturers and suppliers?

Price variation arises from oil formulation quality, refining process, additive technology, testing depth, and brand certification. Some suppliers offer basic mineral oil, while others provide highly inhibited, low-gassing, or fire-resistant oils. Differences in logistics, packaging, and regional production also affect price. Utilities often pay more for suppliers that provide full traceability, batch testing, compliance documentation, and long-term supply guarantees.