The emerging nations are now in the driver's seat of the world economy, according to the chief executive of a major US investment firm at the Forbes CEO conference in Sydney on Tuesday.

Forbes columnist and Fisher Investments founder Ken Fisher told journalists the US was no longer the world's leading economy and would not regain its former position of power.

"The world right now is being led by the emerging markets, not by America," he said.

"It is not the leader it once was.

"It is not in that central role, it is a very important second feature."

Mr Fisher said the "disorganised combined collective emerging markets, which economically are bigger than the US right now," were steering the global economy.

"The emerging markets bottomed out before America did," he said.

"America bottomed out before parts of Europe.

"The US is going to be big and important, but it is secondary, it is no longer what it once was.

"As an American that does not feel right."

Ken Fisher says the economic conditions facing the world today are not dissimilar to previous downturns, like that seen in the early 1990s.

Mr Fisher said he was bullish about the future, unlike five out of six US investors, who "believe we are going sideways or going down'.'

"I believe the next 10 years will be just as good as the 1990s,'' he said.