ExxonMobil will seek a 4 cents/lb ($88/mt) increase in its polypropylene prices, effective May 1, on top of any change in the monomer contract price for the month, the company said Tuesday.

ExxonMobil is the first major North American producer to announce such an increase for May shipments.

In a letter to customers obtained by S&P Global Platts, the company did not specify a reason for the proposed price increase, but market participants have cited expectations of strong demand as the main reason for the increases. Expectations for May deliveries are strong, as are the predictions for April consumption, they said.

In April, four producers have announced plans to increase their PP prices.

Formosa Plastics Corporation USA and two LyondellBasell subsidiaries, Equistar Chemicals and Mexico-based Basell Poliolefinas, plan to raise their North American PP pricing by 5 cents/lb ($110/mt) effective April 1.

Total Petrochemicals & Refining USA and Braskem America are seeking a 4 cents/lb ($88/mt) and 3 cents/lb ($66/mt) increase, respectively, in their PP prices.

The price increases are in addition to any change in feedstock pricing, the companies have said.