Material Insights · Understanding the Material World

Monoethylene glycol and Purified terephthalic acid

MEG and PTA are the two halves of every polyester and PET molecule, bought together by the same plants in a fixed ratio. Both chains are centred on China, where capacity has outrun demand, so their margins have been squeezed at the same time even while polyester plants ran hard.

Monoethylene glycol (chemical) and Purified terephthalic acid (chemical): 4 relationships.

How they are linked

1. Co-reactants in polyester

Shared risk · Strong · Both bought by polyester and PET plants

Polyester is made by reacting PTA with MEG and then polymerising, so every plant needs both in a fixed ratio and neither has a large outlet outside polyester.

  • 87% share of world MEG used in polyester and PET, 2017

PTA and MEG first form an oligomer by esterification, which is then polymerised; unreacted MEG is recovered and recycled. By the chemistry a tonne of polyester needs about 0.86 t of PTA and 0.32 t of MEG, before losses. Because both depend on the same buyers, a polyester slowdown is a common demand shock, while their supply sides differ: PTA comes from paraxylene, MEG from ethylene or coal.

Sources: IHS Markit (S&P Global); Intratec

2. Price link: co-reactant

Cost and price · Strong · Both ways

Both are bought by the same polyester plants and share one demand cycle, but they are made from different feedstocks.

  • 0.33 monthly change correlation
  • 0.80 12-month change correlation
  • 0.84 fitted elasticity

Monthly moves correlate at only 0.33 because the feedstocks, paraxylene for PTA and ethylene or coal for MEG, move on their own. Over a year the common polyester demand dominates and the correlation rises to 0.80.

Sources: Material Insights (World Bank, FRED, IMF data)

3. China dominates both

Geography and ownership · Strong · Both chains centred on China

China has built most new PTA and MEG capacity, so Chinese operating rates and policy set prices for both.

  • 22.4 Mt/yr PTA capacity China was set to add, 2024 to 2028
  • Yuan 180 to 200/t Chinese PTA margin, mid-December 2025
  • 55 to 65% Chinese MEG plant utilisation, 2025

China still imported 6.3 Mt of MEG in January to October 2025, up 16%, because Middle East and North American glycol costs less than much domestic output. Polyester plants ran at about 90% in 2025, so the squeeze sits in the intermediates, not in final demand.

Sources: GlobalData; S&P Global Commodity Insights; S&P Global Commodity Insights

4. India import rules

Policy · High in India · India buys more Chinese PTA after QCO removal

India's quality control order had restricted Chinese PTA; after it was revoked in late 2025, Chinese shipments jumped, which lowers costs for Indian polyester makers, who also buy MEG.

  • 1.95 Mt India PTA imports, January to November 2025, up 9.1% on the year
  • 1.25 Mt/yr planned GAIL Mangalore PTA plant

Chinese PTA shipments to India nearly doubled from November to December 2025, to about 133 kt. A non-Chinese producer said it needs a price at least $100/t above paraxylene to profit, and Indian buyers were rejecting offers near paraxylene plus $70/t.

Sources: S&P Global Commodity Insights

For investors

Key learnings

  1. Polyester takes almost all of both, 87% of MEG in 2017, so a polyester slowdown is a shared demand shock.
  2. Chinese overbuilding cut PTA margins to about Yuan 180 to 200/t (about $26 to $28/t) in December 2025 and left MEG plants at 55 to 65% utilisation, so margins in both stay thin until capacity closes.
  3. The weak monthly correlation (0.33) against a strong yearly one (0.80) reflects different feedstocks but common demand.

What to track

  • PTA to paraxylene spread: Margin for PTA makers; below about $100/t non-Chinese plants lose money (Weekly · Platts, CCF)
  • MEG port inventories, East China: High stocks signal MEG price weakness (Weekly · CCF, Platts)
  • Polyester plant operating rates, China: Demand signal for both (Weekly · CCF, S&P)

For policymakers

Key learnings

  1. India's PTA imports from China rose quickly after the quality control order was revoked; GAIL's planned 1.25 Mt/yr plant would replace part of them.
  2. Quality orders or duties on one co-reactant change the cost of the whole polyester chain, so the two should be judged together.
  3. Middle East and North American MEG undercuts much Chinese output, so MEG trade flows follow feedstock costs more than capacity.

What to track

  • India PTA and MEG imports: Dependence and shifts in origin (Monthly · DGCI&S)
  • India polyester capacity use: Health of the user industry (Quarterly · company reports, Ministry of Textiles)

India

India imported 1.95 Mt of PTA in January to November 2025, and Chinese shipments nearly doubled after it revoked its quality control order late in the year; GAIL's planned 1.25 Mt/yr Mangalore plant would add domestic supply.

Sources

  1. Polyester industry overview, IHS Markit (S&P Global) (2018)
  2. Polyethylene terephthalate production from MEG and PTA (polycondensation): cost report, Intratec
  3. China to spearhead global PTA capacity additions through 2028, GlobalData (2024)
  4. Chemical trends H1 2026: rationalisation, PX and PTA, S&P Global Commodity Insights (2026)
  5. Commodities 2026: global glycols trade flows shift from China amid trade tensions, S&P Global Commodity Insights (2025)
  6. Price correlation, Material Insights, Material Insights (World Bank, FRED, IMF data)
  7. Asian PTA producers under pressure as India laps up Chinese supply, S&P Global Commodity Insights (2026)