Glencore’s (LON: GLEN) exposure to Radiant World, a company with which the London-listed miner and trader has stopped doing new business, amounts to more than half a billion dollars, two sources familiar with the matter told Reuters.

Commodity traders Vitol Group and Cargill have also stopped trading with Radiant World, one of the world’s largest iron ore traders, after invoices or other documents it provided to banks were found to be invalid, Bloomberg reported late last month.

Last week, Glencore CEO Gary Nagle said the Swiss-based commodity trader had taken a provision related to Radiant World, but that its exposure to the iron ore trader was not material. It did not provide a figure for the provision. Glencore’s first-half earnings jumped 86% to top $10 billion.

The sources said Glencore had the largest exposure to any financial problems at Radiant World, at between $500 million and $800 million.

Glencore refuted the report. “The reporting by Reuters is incorrect. As indicated on our earnings call last week, the exposure on our books is not material and well below our threshold of $500m,” it said in a statement.

Glencore’s auditors set materiality for the group’s 2025 accounts at $500 million, based on net assets, meaning inaccuracies below that level are considered too small to distort the figures.

Radiant World was founded by Pinkesh Nahar in the early 2000s, according to its website, which says the company trades more than 20 million metric tons of iron ore annually.

Industry sources say Radiant has built up its iron ore business over the past five years and now trades closer to 75 million tons a year, worth more than $7 billion at current prices SZZFU6.

One of the sources said that volume was large enough to create ripple effects across commodity and financial markets. It could unsettle insurance, banking and debt markets and damage legitimate businesses, the source said.

Radiant World declined to comment.

A third source familiar with the matter said Glencore had been assessing potential losses linked to Radiant World for some time and had already set aside funds and written off some exposure. He said this reflected concerns about commercial and credit risks associated with Radiant rather than a response to recent allegations against the trader.

Glencore’s marketing division traded more than 95 million tons of iron ore last year, up 28% from 2024, according to preliminary results published on its website.

(Reporting by Pratima Desai. Editing by Veronica Brown and Mark Potter)