The Dow Jones index raced past the 24,000 mark for the first time shortly after opening today, propelled by further gains for bank stocks and a recovery in technology shares.
The 30-member index has crossed four similar 1,000-point milestones this year on the back of strong corporate earnings, robust economic data and hopes that US President Donald Trump's tax plan would make headway.
Efforts to push the sweeping tax legislation through the US Senate is hurtling towards a dramatic conclusion, with Republican leaders pursuing behind-the-scenes deals intended to secure enough votes for passage.
"The signs continue to be good, the Republicans are actually moving the ball forward and I think the market is optimistic that it's going to happen," said Brad McMillan, chief investment officer for Commonwealth Financial in Waltham, Massachusetts.
"What happens in the market in the couple of days or weeks is going to depend on whether the Republicans can get this done."
At 4.30pm Irish time the Dow Jones was up 0.75% percent, at 24,119.
The Dow just broke 24,000 for the first time (another all-time Record). If the Dems had won the Presidential Election, the Market would be down 50% from these levels and Consumer Confidence, which is also at an all-time high, would be "low and glum!"— Donald J. Trump (@realDonaldTrump) November 30, 2017
The Nasdaq Composite was up 0.74% at 6,875 a day after posting its biggest one-day drop in more than three months.
A clutch of data has also helped sentiment.
US consumer spending slowed in October but underlying price pressures pushed higher for a second straight month.
The number of Americans filing for unemployment benefits fell last week, dropping for a second straight week as labour market conditions tightened further.
Advancing issues outnumbered decliners on the NYSE by 1,871 to 752. On the Nasdaq, 1,567 issues rose and 895 fell.