Share prices have jumped as investors welcomed official figures that show the cost of living in the US increased at a slower than expected pace last month.
The US consumer price index rose by 7.7% in October from a year earlier, according to the Labor Department.
That is the smallest annual increase since the start of the year and down from 8.2% the previous month.
It means the US central bank may ease its aggressive approach to raising interest rates to tackle inflation.
On Thursday in New York the benchmark S&P 500 index rose by more than 5.5%, while the Dow Jones Industrial Average gained 3.7%. At the same time the technology-heavy Nasdaq soared by 7.35%.