Glencore supplies around 3% of the world's oil consumption, with its biggest customers the oil majors as well as national oil firms in India, Nigeria and Mexico, the company said in the prospectus for its initial public offering.

The company, which estimates it is among the world's largest non-integrated physical suppliers of crude oil and oil products, supplied a physical volume of around 2.5 million barrels of oil a day in 2010.

"This is a volume equivalent to some 3% of the world's oil consumption," the Swiss commodities firm noted. "Glencore's significant customers are the major integrated oil companies such as Royal Dutch Shell PLC (RDSB), BP PLC (BP, BP.LN) and ExxonMobil Corp. (XOM), as well as national oil companies such as Indian Oil Corp Ltd. (530965.BY), Nigerian National Petroleum Company and Petroleos Mexicanos," it added.

In addition, crude oil and oil products are sold to a diverse customer base, including utilities and oil refineries. Glencore said that the percentage of term contracts is "relatively small," but added that this is largely consistent with the structure of the oil market and that spot contracts are primarily with "customers with whom relationships have been established and developed over a long time and are therefore considered similar in nature to term contracts due to their expected renewal."

Glencore's main competitors are Vitol Group, Trafigura Group, Mercuria Energy and Gunvor, all of which are largely asset-light--that is, they own little, if any, upstream production--business models, the Swiss firm said. Glencore also faces marketing competition from banks such as Morgan Stanley and Goldman Sachs, it noted, which have some infrastructure and no current oil production, although the large majority of their business activities involve derivatives and not the physical sourcing and distribution of oil.

Volumes captured by oil majors such as BP and Shell are also in direct competition with Glencore's marketing volumes, it said, although their participation in the market increases overall volume and liquidity.

According to Glencore, it also takes trading positions into account for the purposes of hedging "as well as to take or increase exposures within group limits and policies, where a physically backed position exists, it said."

"The availability of liquid electronic trading markets, covering the majority of the products marketed by the crude oil and oil products operations, enables marketers to hedge their physical oil activities as well as provide profit enhancing opportunities in relation to physical marketing strategies," Glencore noted.

The company is meanwhile also active in supplying natural gas to industrial consumers, with the gas delivered via pipeline in the
U.S. , the U.K. and other parts of Europe .