Welcome to the party, S&P 500.
The benchmark index on Monday hit a new record high for the first time since Aug. 15, breaking above 2,193.81. Leading the S&P higher were energy stocks, which surged around 2 percent on the back of soaring oil prices.
The S&P 500 reached its record on the same day the Dow Jones industrial average, the tech-heavy Nasdaq composite, the Russell 2000 and the S&P Mid Cap 400 all hit record highs. The Dow, Russell, Nasdaq and Mid Cap 400 had also hit record highs last week.
The S&P 500 was also within striking distance of 2,200. In October, a CNBC survey of 15 market strategists showed the average 2016 year-end S&P 500 target was 2,198.
Stocks have seen a sharp spike since the U.S. presidential election, as Donald Trump's surprise victory over heavy favorite Hillary Clinton brought enthusiasm for fiscal stimulus and deregulation of certain sectors, including banks and energy.
"It seems like everything has changed since the election," said Sean O'Hara, director at Pacer Financial. "There is an optimism in the market that hadn't existed."
"We'll have to see if the Trump administration delivers; personally, I think it will," he said.
Robert Pavlik, chief market strategist at Boston Private Wealth, said "I think [this rally] has legs, and it will continue, but there will be some bumps in the road," especially if the U.S. dollar keeps rising.
The dollar index, which tracks the U.S. currency's performance against a six other currencies, eased by 0.14 percent to 101.07 as of 1:09 p.m. ET. Last week, the index hit its highest level since April 2003.
Still, Pavlik said stocks have not given up their gains since the election and, even in days when they have slipped, markets haven't seen any significant continuation of downside trading.