One of the most important features of the US shale oil and gas revolution has been the rolling wave of oversupply that has moved through the energy value chain, creating market imbalances and distorting long-standing price relationships between various hydrocarbons.

Over the past several years, oil and gas companies’ overzealous production of natural gas and natural gas liquids has restored the fortunes of domestic petrochemical producers, an energy-intensive industry that relies on these commodities to generate power and as feedstock.

Within this space, olefin producers have benefited the most thus far, thanks to extraordinarily low feedstock prices. But the multiyear boom in profit margins for US polyethylene producers appears to be winding down, with the baton of profitability likely to move further downstream.