Formosa Chemicals and Fibre (TPE:1326) posted consolidated operating revenue of NT$27.4 billion for May, up 16% from a year earlier, according to a Monday Taiwan Exchange filing.
The annual growth is attributable to higher petrochemical prices driven by oil market volatility and geopolitical disruptions.
Revenue declined 15% from April due to lower sales volumes and weaker pricing.
Shares slid about 1% in Tuesday's afternoon trade.