Polyester fibre: Correlation
Prices it moves with, and why
Polyester fibre is spun from PTA and MEG, or from recycled PET bottles, and is the most used textile fibre in the world. Prices follow paraxylene and glycol costs and compete with cotton; China and India are the main producers.
Price index US PPI: polyester manufactured fibres index (BLS base period) · monthly, Jan 2006 to Sep 2026What its price moves with
Selected linkPolyester fibre and Purified terephthalic acid
Monthly changes 0.14 little or none correlation 12-month changes 0.68 moderate correlation Last 5 years 0.09 monthly changes Lead or lag +1 mo Purified terephthalic acid tends to lead by 1 month (r 0.26) Price function, Jan 2006 to Sep 2026 Polyester fibre ≈ 1.04 × (Purified terephthalic acid)0.89 R² 0.76 On this fit, a 10% higher purified terephthalic acid price goes with a 8.8% higher polyester fibre price over the long run. Units: index (BLS base period) and index (BLS base period).Chart: Polyester fibre and Purified terephthalic acid prices rebased to 100 at Jan 2006, log scale
Both prices rebased to 100 at Jan 2006, on a log scale so equal percentage moves look the same size.Chart: Polyester fibre price against Purified terephthalic acid price, monthly, log scales, with fitted line
Each dot is one month; paler dots are older (2006), darker dots recent (2026); the ringed dot is the latest month. The dashed line is the fitted price function. Both axes are logarithmic.PTA is the larger raw material and is priced off paraxylene, so it sets most of the fibre cost. The cyclic intermediates proxy moves with the fibre index at 0.14 monthly and 0.68 yearly, as fibre prices adjust with a lag.
little or none co-movement month to month · 249 months Show chartsMEG is the second monomer, bought together with PTA. The basic organics proxy moves with the fibre index at 0.17 monthly and 0.65 yearly. Chinese coal-based glycol keeps a lid on its cost in Asia, where most fibre is spun.
little or none co-movement month to month · 249 months Show chartsPolyester and cotton compete in yarn and fabric, and mills shift blends when cotton is dear. Cotton moves with the fibre index at only 0.07 monthly and 0.35 yearly, since cotton follows harvests, weather and farm policy.
little or none co-movement month to month · 249 months Show chartsRecycled PET bottle flake is a major feed for staple fibre, and virgin PET resin is made on similar lines. The resin proxy moves with the fibre index at 0.24 monthly and 0.42 yearly.
weak co-movement month to month · 249 months Show chartsOil sets the cost of naphtha and so of paraxylene, PTA and fibre. Brent moves with the fibre index at 0.14 monthly and 0.56 yearly, a loose tie as spinners' margins absorb short swings.
little or none co-movement month to month · 249 months Show chartsHow to read these numbers
Correlation of monthly changes (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak.
12-month changes compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs.
Price function is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation.
Lead or lag checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months.
Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link.
Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site.