The prompt October/November inter-month spread slipped a dollar to a three-session low of $9.00 a tonne in backwardation, according to Reuters data.
A recent hike in prices, supported by strong gasoline demand in the West, has hurt petrochemical margins. Concerns over slower manufacturing activities have also risen, traders said.
Fuel oil's inter-month spreads remained weak on ample supply and lacklustre demand.
The gasoil market, on the other hand, received a boost as a drop in European inventories would see Asian stocks being shipped to the West.
Gasoil's October/November inter-month spread strengthened to a two-week high of 60 cents a barrel in backwardation, Reuters data showed.
Japanese stocks for the week to Sept. 29 fell three percent to 1.73 million kilolitres, data by the Petroleum Association of Japan showed.
Fixed-price swaps for all products weakened, with Brent crude losing 99 cents to $111.15 per barrel by 0430 GMT from Tuesday's Asian close.