The fact that the stock market wants to climb even higher is "stunning" but true, widely followed investor Dennis Gartman told CNBC on Thursday.
The Dow Jones industrial average soared more than 350 points on Thursday, breaking above 24,000 for the first time, on optimism over tax reform.
"You're at this point in the stock market where it can do anything. It's gone parabolic," the editor and publisher of The Gartman Letter said in an interview with "Power Lunch."
"It is stunning to me, surprising to me, but it still wants to go up."
The odds of success increased for the Republican Senate tax bill on Thursday after Sen. John McCain said he would support the legislation. The upper chamber is expected to vote later in the day.
If it passes, the House and the Senate will have to work together to reconcile the two bills and then send the final legislation to President Donald Trump to sign.
Gartman said the bull market "will stop eventually." He thinks that may occur when the Federal Reserve begins to tighten monetary policy aggressively.
Gartman has been calling the stock market "egregiously overpriced" and recently predicted when the bull market does end, it "will end badly."
Earlier Thursday, billionaire activist investor Carl Icahn told CNBC he thinks the market has "gotten into a euphoric state."
However, he also acknowledged a lot of underlying strength in the market.
"It's run away and there might be a big correction but I can't say it's insane," Icahn said.
— CNBC's Liz Moyer and Brenda Hentschel contributed to this report.