Qatar Holding, the investment arm of the Gulf state's sovereign fund, is in advanced talks to buy a 49-percent stake in Brazilian billionaire Eike Batista's gold company AUX for about $2 billion, three banking sources said.

Batista, Brazil's richest man, said in June that he expected to sell the AUX stake, which owns gold mining rights in Colombia, for about $2 billion by September.

The gold company, created in 2010, is part of Batista's EBX holding company.

Talks between the two parties are in advanced stages and an agreement may be reached as early as this month, one of the sources said, declining to be identified as the matter has not been made public.

Swiss bank Credit Suisse (CSGN.VX) is advising Qatar Holding on the transaction, while Brazil's Itau Unibanco (ITUB4.SA) (ITUB.N) is advising the seller, the sources said.

EBX officials were not immediately available for comment outside business hours in Rio de Janeiro. An email sent to Qatar Holding seeking comment remained unanswered.

Brazil's Veja magazine said on Sunday that Batista will soon announce the sale of a 49-percent stake in AUX to Qatar's sovereign wealth fund.

Qatar Holding is a unit of the Qatar Investment Authority (QIA), the sovereign fund which has around $100 billion in assets and owns stakes in a wide range of businesses including London's famed Harrods department store and German car maker Porsche (PSHG_p.DE).

The fund also holds a 12-percent stake in Xstrata (XTA.L) which has put it center stage in Glencore's (GLEN.L) battle to take over the London-listed miner.

"Qatar likes commodities, especially gold, and considers it an attractive long-term investment play. They are scouting for such assets globally and AUX fits in perfectly in that criteria," the source, who is not directly on the deal, said.

In April, a top QIA executive said the fund has closely watched the performance of commodities since 2002 and sees a further rising trend in prices in 2016 and 2017, making such investments highly attractive.

Qatar Holding passed on a $1 billion investment in European Goldfields last year after the company instead agreed on a $2.4 billion takeover by Canadian group Eldorado Gold (ELD.TO).

Batista, who controls investment holding company EBX Group and has assets spanning oil, mining, rig-building and ports, has been raising more capital to fund his cash-hungry empire.

In March, Abu Dhabi state investment fund Mubadala MUDEV.UL bought a $2 billion stake in EBX.

The billionaire, who was previously chairman of Toronto-based TVX Gold Inc, canceled plans to buy back shares in and delist his logistics company LLX (LLXL3.SA) earlier in September after an independent valuation.