The Dow and the S&P 500 Thursday bolted to new records after the European Central Bank launched aggressive measures to stimulate fragile eurozone growth and avert deflation.
The Dow Jones Industrial Average advanced 98.58 points (0.59 percent) to 16,836.11 while the broad-based S&P 500 rose 12.58 (0.65 percent) to 1,940.46.
The tech-rich Nasdaq Composite Index posted strong gains, leaping 44.58 (1.05 percent) to 4,296.23.
US markets reacted enthusiastically to a series of new measures from the ECB, which lowered all three of its key interest rates, including putting the deposit rate into negative territory for the first time, meaning banks will be charged for depositing their excess cash with the central bank.
"Expectations were for them to take action and the market is applauding the action that has been taken," said David Levy, portfolio manager at Kenjol Capital Management.
Analysts said the ECB's new push means liquidity will remain at high levels globally even as the Federal Reserve scales back its asset-purchase stimulus.
Levy said a 1.8 percent gain in the Russell 2000, a leading index of small cap stocks, was particularly bullish.
"It shows confidence in the market that investors are willing to invest in riskier stocks," he said.
Leading banks had a good day, including Dow member JPMorgan Chase (+1.7 percent), Citigroup (+1.6 percent) and Wells Fargo (+1.2 percent).
General Motors fell 0.7 percent after chief executive Mary Barra announced the company fired 15 employees over the deadly ignition scandal and uncovered a pattern of "incompetence and neglect" behind the debacle.
US telecom giant Sprint is nearing a deal valued at about $32 billion to acquire rival T-Mobile, according to the Wall Street Journal and others. Sprint fell 4.0 percent, while T-Mobile dropped 2.3 percent.
Amazon jumped 5.5 percent on anticipation of a June 18 mystery event with founder Jeff Bezos. Topeka Capital Markets said the buzz is that Amazon will launch a smartphone, which could boost subscriptions to its "Prime" service.
Videogame developer Zynga sank 9.2 percent on concerns about a conference presentation from chief Don Mattrick. Mattrick "seemed slightly less upbeat" than normal about the company's prospects, said a note from Sterne Agee.
Bond prices rose. The yield on the 10-year US Treasury fell to 2.58 percent from 2.61 percent Wednesday, while the 30-year dropped to 3.43 percent from 3.45 percent. Bond prices and yields move inversely.