Asian shares rose more strongly than those in Australia or New Zealand.
Craigs Investment Partners broker Chris Timms said that was because Asian shares fell on Thursday before the Fed announcement.
Australian shares fell, but not as much and the NZX had stayed firm.
The Fed announced it would buy $US40 billion ($NZ48 billion) a month of mortgage-backed debt until the outlook for jobs improved substantially and as long as inflation remained contained, acting on its dual mandate to maintain low inflation and tackle unemployment.
The Fed also said it was unlikely to raise interest rates from current lows until at least mid-2015, extending the time frame for such a move from late 2014.
The Fed decision to introduce the newest (third) round of quantitative easing, or QEIII, was more like "QE infinity", Mr Timms said.
With moves in Europe to install a bail-out mechanism, the Fed flooding the market with money and China talking about stimulatory infrastructure projects, the three largest influencers could be creating a bull market.
"Governments are showing they are prepared to do what it takes to get through this cash crisis."
However, getting a resolution was a long way off, he said.
Governments were more likely to be seen muddling their way through for several more years.
Asked whether sharemarket strength would remain, Mr Timms said that as long as differential remained large between what New Zealand investors could receive from interest in the bank and sharemarket returns, the NZX would move up in value.
The delay in the float of Mighty River Power left people with money they needed to invest.
But overseas developments would contribute to the ebb and flow of the value of the NZX, he said.
Jeff Sica, chief investment office of Sica Wealth Management, which manages more than $US1 billion in client assets, real estate and private equity holdings, now sees gold as the ultimate investment in the face of mass liquidity creation and the weakening dollar.
"The appeal of gold as a shelter from fear and a secondary currency has never been greater," he said in an email to Reuters.
Mr Sica doubted market euphoria would last long, because investors would soon shift their focus to the weak economic fundamentals and the risk of relying heavily on a government entity for its growth.
"As the US central bank takes this responsibility and commits to its execution, any attempt to return to an economy that relies on free market fundamentals will be extremely difficult. The Fed has crossed the point of no return," he said.
Unlike in its two previous bond-buying sprees, the Fed said it would only buy mortgage-backed securities, hoping in part to unstick a housing sector that chairman Ben Bernanke called "a missing piston" in the US recovery.
One top Republican charged that the move was a bid to help President Barack Obama before the closely contested presidential election in November.
Republican nominee Mitt Romney's campaign said it confirmed the failure of Mr Obama's policies.
Mr Bernanke dismissed talk the Fed was taking sides, saying it acted solely because of the dire state of the US labour market.
"The employment situation ...remains a grave concern," Mr Bernanke said.
"While the economy appears to be on a path of moderate recovery, it isn't growing fast enough to make significant progress reducing the unemployment rate."
