The world share index has surged 17.6 per cent so far in 2017.
"The continuation of quantitative easing (QE) in Europe at a time when Japan remains locked on QE and the US is only tightening gradually highlights that global monetary conditions will remain easy for a long while yet," said Shane Oliver, head of investment strategy at AMP Capital.
"This along with strong economic growth and earnings, largely explains why global share markets are so strong."
On Friday, the Nasdaq added 2.2 per cent, the S&P 500 climbed 0.81 per cent and the Dow rose 0.14 per cent.
Amazon, up 13.2 per cent, was responsible for the biggest boost to the S&P 500 after reporting a quarterly sales surge.
Tech giant Apple Inc is due to report on Thursday.
The dollar index was a touch softer, after two straight days of gains helped by upbeat third-quarter US GDP data. The US economy grew at a 3.0 per cent annualised rate from July to September, showing resilience after recent storms.
Investors are now focused on the impending appointment of the Federal Reserve chair, with speculation rife that Fed governor Jerome Powell is the favoured suitor.
Wagers that Powell, who markets see as a less hawkish candidate, will be the chosen one tempered the dollar's advances and dragged 2-year Treasury yields off a nine-year top. An announcement is expected this week.
"Markets are evidently still intent on having some fun, speculating on whether the next Fed chair will be trying to pull the Fed in a more hawkish direction or whether continuity will be the name of the game," said Ray Attrill, head of FX strategy at National Australia Bank.
In Europe, political uncertainty and the ECB together weighed on the common currency, marking its biggest weekly loss of the year.
The euro steadied at $1.1602, not far from $1.1573 which was the lowest since July 20.
Spain sacked Catalonia's regional government on Friday, dissolved the Catalan parliament and called a snap election after Catalonia declared independence from Spain.
The ECB's decision last week to extend its bond purchases into September 2018 also hurt the euro, driving yields on two-year German bunds lower.
The premium that 2-year US debt pays over 2-year German yields is now the widest since mid-1999, making it more attractive to borrow in euros to buy dollars.
In commodities, Brent crude rose to $60.63 per barrel, the highest since July 2015, after Saudi Arabia agreed to support the extension of a global oil production cut agreement.
US crude ticked up 0.32 per cent at $54.07 a barrel.
Spot gold was trading 0.1 per cent lower at $1271.20 per ounce.