The men set to become billionaires. But who are they?

It has been called the biggest company you've never heard of, and this highly secretive business is about to make its partners some of the richest people on the planet.

When commodities trading firm Glencore floats on the London and Hong Kong stock exchanges later this month, 485 of its employees will put bankers' bonuses in the shade by effectively divvying up $60bn (£36.6bn) between them – giving them an average share of $103m each.

The biggest winner will be Glencore's South African chief executive, Ivan Glasenberg, who has $9bn coming his way if estimates of his 15 per cent stake are accurate. The Swiss-based company, whose staff are described by the Reuters news agency as "young, arrogant, and often brilliant", increased its profits by 40 per cent to $3.8bn last year.

It is the largest of the world's big four independent oil dealers, ahead of Trafigura, Vitol and Gunvor. The same quartet provoked controversy in 2009 by using fleets of oil tankers to store their valuable cargo off-shore during a glut of availability, waiting for its value to increase before selling it on for profits of 15 to 20 per cent.

Oil is not Glencore's only business, however. It also makes its money from trading in other key global commodities such as copper, iron ore and sugar, and has huge stakes in logistics and mining companies. This includes a third of Xstrata, which in itself is worth $65bn.

Recent volatility in world stock prices, caused by the Japanese earthquake, tsunami and nuclear crisis had been expected to delay its flotation by several weeks. But the company is now widely expected to finally make a formal announcement of its flotation plan on Thursday. That could raise between $10bn and $12bn, even with only a fifth of its shares going on sale.

These shares are currently all owned privately by partners, but potential investors – the likes of fund-managing behemoth BlackRock and the Abu Dhabi Investment Authority – are said to be queuing up to buy.

The top 12 Glencore executives are a particularly select bunch, owning 31 per cent of the company according to Forbes magazine. Willy Strothotte, the company's 66-year-old chairman, is another man about to shoot up that magazine's list of billionaires, while the company's Chief Financial Officer Steven Kalmin and oil director Alex Beard will also do well. None of these men will be able to start spending their vast fortunes straight away, however, having agreed not to sell up immediately. The flotation is not for their short-term benefit, but is designed to give the company fresh capital and allow it to grow the business even more.

Glencore will attract even more attention if it goes through with its apparent plan to appoint a senior non-executive director in the form of Tony Hayward, the former BP head who encountered worldwide derision following his handling of the Gulf of Mexico oil spill last year.

The company is no stranger to controversy. Last week one of its traders was arrested in China as part of an investigation into alleged tax evasion, although the company has since staunchly denied any wrongdoing. Glencore was set up by Marc Rich, an American financier who fled from his home country while he was being prosecuted for making illegal oil deals during the Iran hostage crisis of 1979-81. He was charged with 51 counts of tax fraud, after evading payments of $48m.

Mr Rich was pardoned by President Bill Clinton, a decision that caused outrage in Washington and prompted an investigation into political donations made by his ex-wife, Denise, though she denied any wrongdoing and no charges were brought.

Mr Rich severed his ties with Glencore in 1994, taking home $600m in the process, but he has said he plans to re-invest when Glencore goes public.