Markets rose on Tuesday.
The S&P 500 rose 0.3 percent, the STOXX Europe jumped 1.5 percent and the Nikkei 225 surged 3.7 percent, reversing Monday's steep fall.
Stocks were boosted by oil. US crude oil jumped 3.3 percent on Tuesday.
Despite US stock indices approaching record highs, some remain unconvinced of the sustainability of the rally.
“You’ve got to temper short-term enthusiasm with a reality check,” said Bill Nichols, head of US equities at Cantor Fitzgerald.
“It’s hard to imagine this thing going much higher without positive earnings growth,” said Tom Carter, managing director at brokerage JonesTrading.
Indeed, Michael Pento, president of Pento Portfolio Strategies, thinks “a stock-market sell-off of 25 percent or more will happen if the Fed can't get the dollar into a bear market”.