The SP 500 and Dow Jones closed at record highs on Thursday after Federal Reserve chairman Ben Bernanke said again that monetary policy will remain accommodative for some time.
The Dow Jones Index closed up 1.1%, at 15,461. The SP 500 index gained nearly 1.4% to 1,675
And the Nasdaq Composite closed up 1.6% at 3,578 - its highest close since October 2000.
In London, the FTSE closed up 0.59%, the DAX in Frankfurt closed up 1.37% and the CAC-40 in Paris was up 0.74%.
Mr Bernanke said in Massachusetts the Fed's economic stimulus programme remains necessary because US unemployment is too high and inflation is too low.
The ABC reports he hinted that there would not be any changes to the economic stimulus until employment increases and prices become stable.
"Currently we have an unemployment rate of 7.6%, which I think if anything, overstates the health of our labour markets," he said.
"On price stability, inflation is now about 1%, which is below our 2% objective. So both sides of our mandate are saying that we need to be more accommodative."
In May, Mr Bernanke hinted that the Fed may scale down its programme of bond purchases if growth forecasts for the US economy improve. The comments caused financial markets around the world to fall.
The Australian 200 Index closed up 1.3% at 4,966 points while the NZX50 gained only 3 points to close at 4,560. However, this was its sixth consecutive daily rise.
At 8.30am on Friday, the New Zealand dollar was trading at about 78.5 US cents - down about a cent on Thursday night. It was trading at Australian 85.43 cents.
Brent crude oil was flat at nearly $US109 per barrel and gold was $US1282 per ounce.
