New York - A few years ago Brazilian tycoon Eike Batista brashly predicted he would become the world's richest man.

Now, he has been ingloriously dumped from the ranks of billionaires.

Batista, whose fortune early last year was put at $30 billion (S$38 billion), is now merely a multi-millionaire, Forbes magazine said, announcing his delisting from the ranks of the world's wealthiest on Monday.

The comedown followed the implosion of Batista's heavily leveraged mining, energy and logistics empire, wiping out more wealth in less than two years than all but a handful of the world's billionaires even have to their credit.

"Batista, who told Forbes in 2010 he would become the world's richest man, is now worth less than $900 million," the magazine said.

Batista's oil and gas giant OGX has lost 90 per cent of its value this year and, as Forbes pointed out, not only are key institutions dumping the shares, but Batista himself is selling to raise money to pay off his EBX group's debts.

Meanwhile his power generation company MPX said last week it would change its name to cut the link it has with Batista.

The precipitous drop in wealth came on the back of the slump in global mining and the revelations that oil wells drilled by OGX produced a bare fraction of what they had been reported to produce.

With the meltdown in Brazil's stock market and creditors baying, Batista has vowed to pay off all of his group's debt.

On Thursday he announced the sale of 1.5 per cent of OGX as well as the sale of 5.4 per cent of OSX, his offshore oil services group.

Click here for the gallery on Forbes billionaires