Over the last decade, the global ethylene industry has undergone significant change and evolution. New production centres have emerged, while high crude oil/gas price ratios and lower global demand at the start of the decade led to the closure of ethylene capacity in other regions. Since then, the market has rebalanced and even entered periods of tightness over the past few years. Coupled with lower crude/oil gas ratios, this tightening has flattened the global ethylene cost curve. So what can we expect from the next investment cycle?