Lactic acid and PLA: Correlation
Prices it moves with, and why
Lactic acid is fermented from sugar or corn dextrose and polymerised into PLA. Its price rests on sugar costs and a few large plants, and PLA sells at a premium that must compete with cheap fossil plastics and policy-driven demand.
No public price Lactic acid and PLA has no public monthly price series: A few producers sell on contracts; no public price index.What its price moves with
One of the largest PLA plants, in the US, ferments dextrose made from corn, so maize sets a large share of its cost. Feedstock is a smaller part of the final price than for bulk chemicals because fermentation and polymerisation are costly.
Not enough overlapping price history to measure.Plants in Thailand and Europe ferment cane or beet sugar, so world sugar prices matter directly. Cheap sugar is a key reason new PLA capacity is built near cane fields in Southeast Asia.
Not enough overlapping price history to measure.PLA competes with PET in bottles, food trays and films. When oil-based PET is cheap, the price gap widens and buyers stay with PET unless rules on compostable or bio-based packaging require otherwise.
Not enough overlapping price history to measure.PLA replaces polystyrene in cups, cutlery and clamshells, often driven by bans on single-use polystyrene. The price of polystyrene sets how large a premium buyers will pay for the compostable option.
Not enough overlapping price history to measure.Conventional fermentation neutralises lactic acid with lime and frees it with sulphuric acid, leaving gypsum waste. Newer plants reduce this step, but acid and lime remain a cost for many producers.
Not enough overlapping price history to measure.How 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.