Material Insights · Understanding the Material World

Platinum and Rhodium

Rhodium is a small by-product of the same South African reefs that are mined for platinum and palladium, so its supply follows platinum-group mining decisions rather than its own price, which is why rhodium prices swing far more than platinum's.

Platinum (commodity) and Rhodium (commodity): 4 relationships.

How they are linked

1. Rhodium rides on platinum-group mining

Joint production · Asymmetric · Platinum-group ore mining → rhodium

Rhodium is recovered as a minor by-product of platinum-group ores, so its output depends on how much ore miners treat for platinum and palladium, not on rhodium demand.

  • over 80% South Africa's share of world mined rhodium
  • about 583,000 oz world primary rhodium supply, 2020
  • 120,000 kg South Africa's platinum mine output, 2025 estimate

South Africa also dominates platinum, ahead of Russia (about 20,000 kg in 2025) and Zimbabwe (about 18,000 kg). When South African output fell by an estimated 9% in 2025, blamed on weak palladium prices, deep-mining costs and power cuts, rhodium supply fell with it whatever its own price was doing.

Sources: USGS; International Platinum Group Metals Association; S&P Global Platts

2. Same smelters and refineries

Shared risk · Strong · A South African processing outage hits both

Both metals pass through the same South African smelting and refining chain, so a fault at one converter plant cuts platinum and rhodium output together.

  • about 1 million oz platinum-group work-in-progress stock built up after Anglo American Platinum converter problems, 2020
  • above $25,000/oz rhodium price on 25 February 2021, a first

The 2020 outage at Anglo American Platinum's converter plant at Waterval left metal locked inside the process for months. Platinum was affected too, but rhodium, with a much smaller market and no other large source, reacted far more sharply. Power supply problems in South Africa are a standing version of the same shared risk.

Sources: USGS; S&P Global Platts

3. Exhaust catalysts, glass and nitric acid

Shared risk · Strong · Both sold to carmakers and chemical users

Catalytic converters are the leading US use of platinum-group metals and take about 85% of world rhodium demand; the two metals are also alloyed together in glass-making hardware and in catalyst gauzes that turn ammonia into nitric acid.

  • 85% share of rhodium demand from autocatalysts
  • 9% share of rhodium demand from chemical catalysis

Because both depend on vehicle catalysts, tighter emission rules raise demand for both, as in the 2021 rally, which S&P linked to stricter emission standards worldwide and strong demand from China and Europe. A shift to battery cars, which need no exhaust catalyst, would cut demand for both together.

Sources: USGS; International Platinum Group Metals Association; S&P Global Platts

4. Rhodium swings far more than platinum

Cost and price · Asymmetric · Platinum-group supply shocks → amplified rhodium price moves

Rhodium's tiny, by-product supply cannot respond to price, so the same shocks that nudge platinum can multiply rhodium's price several times over.

  • $4,660/oz average rhodium price, 2024
  • $5,800/oz average rhodium price, 2025 estimate
  • $1,200/oz average platinum price, 2025 estimate

Rhodium went above $10,000/oz in 2008 and above $25,000/oz in 2021, and each spike pushed carmakers to cut its use as far as possible, which later deepened the fall. In 2025 the average prices of rhodium and platinum rose by similar amounts, about 24% and 25%, showing the two can also move together when the whole platinum-group complex tightens.

Sources: USGS; International Platinum Group Metals Association; S&P Global Platts

For investors

Key learnings

  1. Rhodium supply is set by platinum-group mining in South Africa, so rhodium prices respond to mine closures, power cuts and smelter faults rather than to rhodium demand alone.
  2. Price spikes in rhodium trigger thrifting by carmakers, so very high prices tend to cut future demand and set up sharp falls.
  3. Both metals share the autocatalyst market, so vehicle emission rules and the pace of battery car adoption move them in the same direction.

What to track

  • South African platinum-group metal output: Falls cut rhodium supply more sharply than platinum supply (Monthly · Statistics South Africa mining production)
  • Rhodium to platinum price ratio: A rising ratio signals tight by-product supply and a risk of thrifting (Daily · Johnson Matthey base prices)
  • Smelter and converter outages at major producers: Can lock up platinum-group metal stocks for months (Quarterly · company production reports)

For policymakers

Key learnings

  1. Supply of both metals is concentrated in one country, so electricity and logistics in South Africa are a supply risk for every user of exhaust catalysts.
  2. Because rhodium cannot be mined on its own, recycling spent catalysts and holding stocks are the main buffers against shortages.
  3. Emission standards create demand for both metals at once, so tighter rules should be weighed against supply concentration.

What to track

  • South African power supply and load shedding: Directly limits output of both metals (Weekly · Eskom system status)
  • Autocatalyst recycling volumes: A secondary source that reduces dependence on South African mines (Yearly · Johnson Matthey PGM market report)

Sources

  1. Mineral Commodity Summaries 2026: Platinum-group metals, USGS (2026)
  2. Rhodium factsheet, International Platinum Group Metals Association (2026)
  3. Rhodium surges past $25,000/oz on tight supply, strong demand, S&P Global Platts (2021)