Why are Basic Chemicals prices diverging across the supply chain?

Why are Basic Chemicals prices diverging across the supply chain?
Basic Chemicals are splitting into tiers. Benzene, ethylene glycol and PTA sit in extreme tightness, with benzene inventory down nearly 80% year on year and PTA destocking 410,000 tons in a single week. Methanol, styrene and polyolefins are tight but less extreme, while caustic soda, soda ash, urea and glass carry high or seasonal-record inventories and rise mainly on sentiment. The divide is driven by low inventory plus geopolitical disruption to Middle East supply routes, not by broad demand recovery. Cost push distributes profit unevenly: resource-adjacent products hold margins, while mid-chain and downstream producers absorb the squeeze.