# Rhodium: Correlation Prices it moves with, and why Source page: https://www.materialinsights.org/commodities/rhodium/correlation/ Rhodium is a tiny by-product market from platinum mines, mainly in South Africa. Almost all goes into catalytic converters to cut nitrogen oxides, so prices swing wildly with car demand, emission rules and South African output. No public price Rhodium has no public monthly price series: Thin dealer market; no free public price series. #### What its price moves with Commodity [Pt Platinum](https://www.materialinsights.org/commodities/platinum/)Co-product Rhodium comes out of the same South African ore as platinum, in much smaller amounts, so its supply depends on platinum mining rates rather than on rhodium prices. That makes its price unusually volatile. Not enough overlapping price history to measure. Commodity [Pd Palladium](https://www.materialinsights.org/commodities/palladium/)Catalyst partner Petrol car converters use palladium to oxidise pollutants and rhodium to reduce nitrogen oxides, so both follow petrol car production and emission rules. Carmakers have worked to cut rhodium loadings after its price spike. No public price for palladium, so the link is explained in words only. Chemical [PGM Autocatalysts](https://www.materialinsights.org/chemicals/autocatalysts/)Main use Catalytic converters use most rhodium, and no other metal cuts nitrogen oxides as well in petrol engines. Tighter emission rules in China and Europe drove the price spike earlier this decade. Not enough overlapping price history to measure. Energy [ICV Combustion road vehicles](https://www.materialinsights.org/energy/e_road_ice/)Car demand Combustion and hybrid vehicle production sets rhodium demand, and electric cars need none. A small change in car output moves rhodium a lot, because supply cannot respond for years. Car forecasts therefore drive the market. Not enough overlapping price history to measure. Chemical [HNO3 Nitric acid](https://www.materialinsights.org/chemicals/nitric_acid/)Catalyst use Nitric acid plants oxidise ammonia over platinum-rhodium gauzes, which slowly lose metal and are refined and replaced. It is a small but steady use linked to fertiliser and explosives production. 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. ## Other sections - [Summary](https://www.materialinsights.org/commodities/rhodium/index.md) - [Overview](https://www.materialinsights.org/commodities/rhodium/overview/index.md) - [Extraction](https://www.materialinsights.org/commodities/rhodium/extraction/index.md) - [Production](https://www.materialinsights.org/commodities/rhodium/production/index.md) - [Stocks](https://www.materialinsights.org/commodities/rhodium/stocks/index.md) - [Cycles](https://www.materialinsights.org/commodities/rhodium/cycles/index.md) - [Trading](https://www.materialinsights.org/commodities/rhodium/trading/index.md) - [Movement](https://www.materialinsights.org/commodities/rhodium/movement/index.md) - [Criticality](https://www.materialinsights.org/commodities/rhodium/criticality/index.md) - [Characteristics](https://www.materialinsights.org/commodities/rhodium/characteristics/index.md) - [Emissions](https://www.materialinsights.org/commodities/rhodium/emissions/index.md) - [Relationships](https://www.materialinsights.org/commodities/rhodium/links/index.md)