"We are not going to have a collapse like the '08, but there is a good chance that we have experienced the new highs and the market is starting to roll over to what may be the start of a bear market."
On Wall Street, shares of FedEx dropped 4.5 per cent after the company warned that the economy wasn't as strong as it had anticipated, paring its earnings forecast.
"What we're seeing at the moment ... is we just don't have as strong an economy as we would have hoped it would be a year ago," Chief Financial Officer Alan Graf told analysts on a conference call, according to Reuters.
Even so, the latest data on the world's biggest economy keep pointing to strength.
A report from the New York-based Conference Board showed its leading economic index rose 0.7 per cent during February, gaining for a fifth straight month.
The labour market also remains on track for improvement, as jobless claims unexpectedly fell. Initial claims for state unemployment benefits slid 5,000 to a seasonally adjusted 348,000 last week, the lowest level since February 2008, according to the Labor Department. Economists polled by Reuters had forecast claims rising to 354,000.
"The economy is entering a phase where more of the gains from growth accrue to labour rather than capital and we believe that stronger job creation will be sustained throughout 2012," John Ryding, chief economist at RDQ Economics in New York, told Reuters.