Polypropylene: Correlation
Prices it moves with, and why
Polypropylene is polymerised from propylene and used in packaging, car parts, fibres and household goods. Propylene sets most of its cost, and prices also follow propane, oil, and the wave of Chinese plants that made China an exporter.
Proxy US PPI: thermoplastic resins and plastics materials index (BLS base period) · monthly, Jan 2006 to Sep 2026There is no free public price for polypropylene itself, so this tab uses the closest public series as a stand-in. Read the numbers as an indication, not as the price of this exact item.
What its price moves with
Selected linkPolypropylene and Propylene
Monthly changes 0.71 strong correlation 12-month changes 0.89 strong correlation Last 5 years 0.85 monthly changes Lead or lag none No clear lead or lag Price function, Jan 2006 to Sep 2026 Polypropylene ≈ 100.1 × (Propylene)0.17 R² 0.09 On this fit, a 10% higher propylene price goes with a 1.6% higher polypropylene price over the long run. Units: index (BLS base period) and index (BLS base period). The fit is loose, so treat the function as a rough guide.Chart: Polypropylene and Propylene 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: Polypropylene price against Propylene 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.Propylene is nearly all of the raw material cost, and many plants are integrated with crackers or propane dehydrogenation units. The petrochemical proxy moves with the resin proxy at 0.71 monthly and 0.89 yearly.
strong co-movement month to month · 249 months Show chartsPropane dehydrogenation now supplies much of the propylene for new Asian polypropylene plants, so propane prices feed directly into costs. Mont Belvieu propane moves with the resin proxy at 0.20 monthly and 0.75 yearly.
weak co-movement month to month · 248 months Show chartsPropylene from naphtha crackers and refineries ties polypropylene to oil. Brent moves with the resin proxy at 0.24 monthly and 0.72 yearly, a loose monthly tie as resin margins swing with supply.
weak co-movement month to month · 249 months Show chartsPolypropylene and polyethylene compete in packaging, film and moulded goods, so a wide price gap shifts demand. They share the same proxy index here, so no separate statistics are shown.
Not enough overlapping price history to measure.Cars use polypropylene for bumpers, dashboards and battery cases. The vehicle price proxy does not move with the resin proxy, -0.02 monthly, because car prices are set by model cycles, not by resin costs.
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.