LONDON (BLOOMBERG, REUTERS) - Institutional investors in Glencore will sue the world's biggest commodities trader and one of its largest mining companies for share price declines from bribery investigations in the US, the UK and Canada, a law firm representing them said after the latest probe was announced.

Boies Schiller Flexner said the suit is "expected to run into the billions," after Glencore disclosed on Thursday (Dec 5) that the UK's Serious Fraud Office was investigating it, sending its shares plunging. The investigation comes on the back of overlapping inquiries in the US and Canada that have helped drive Glencore's stock down in the past 18 months.

"Whilst we have been working on the claim for a number of months now, and have secured litigation funding as well as provision for adverse costs, today's announcement that the SFO is opening an enquiry into bribery at Glencore can only serve to strengthen the claims of institutional investors," Natasha Harrison, Boies Schiller's managing partner in London, said in a statement.

A spokesman for Glencore declined to comment.

The London-listed shares of Glencore, which has operations in over 150 countries, fell 9 per cent to 216.9 pence on Thursday, their lowest level in more than three years, knocking £2.6 billion (S$4.65 billion) off the company's market value.

The probes have raised questions about how commodities trading is conducted around the world, notably in Brazil, where Glencore is under investigation in connection with the country's massive "carwash" scandal.

The suit Boeis announced is the latest in a string of bad news for Glencore that has clouded the final stretch of chief executive officer Ivan Glasenberg's tenure. Glasenberg has said he is planning to step down soon. Dealing with the investigations has become a major part of his role.

The London-listed shares of Glencore, which has operations in over 150 countries, fell 9 per ceny to 216.9 pence, their lowest level in more than three years, knocking £2.6 billion pounds (S$4.65 billion) off the company's market value.

Glencore was subpoenaed in July 2018 by the US Department of Justice over possible violations of the Foreign Corrupt Practices Act relating to operations in Nigeria, Venezuela and the Democratic Republic of Congo (DRC).

Two sources familiar with the matter said the SFO had recently sought information relating to Glencore's involvement in the DRC and its former business partner, Israeli billionaire businessman Dan Gertler.

Reuters was unable to ascertain whether those enquiries were part of the SFO's bribery probe.

Gertler was sanctioned by the United States in 2017 over allegations he used his friendship with former DRC President Joseph Kabila to secure sweetheart mining deals. He denied all allegations of impropriety at the time.