The index rose as much as 0.57% to a record high of 2872.87 in afternoon New York trading, topping the previous record set on 26 Jan.
Investors were cheered by strong company earnings, the expanding economy and hopes that the United States and China could resolve their trade dispute.
The index has been on a tear for 3,452 days or more than nine years, and, on Wednesday, will mark the longest bull run in history.
The previous longest stock rally ran from October 1990 to March 2000.
“Investors, overall seem more optimistic that the troubles with global trade may get resolved this week,” said Kate Warne, principal and investment strategist at Edward Jones in Des Peres, Missouri.
“We’ve seen a continuation of strong earnings and signs of stronger economic growth and you would expect investors to be confident in this kind of an environment and expect stocks to rise.”
At the close of trading on Wall Street, the S&P 500 was off its high for the day, up 0.18% to 2862.41, the Dow Jones Industrial Average rose 0.25% to 25,822.02 and the tech-heavy Nasdaq Composite was up 0.45% at 7855.01.