CNBC's Jim Cramer said Thursday that he's grown worried about the stock market's ability to continue its robust rally from the coronavirus-driven bottom.
"I'm feeling uncertain here after a very big run, fourth-quarter 1999-like," Cramer said on "Squawk Box," a reference to the run-up in equity prices that preceded the 2000 dot-com bubble bust.
Shortly after Cramer's remarks Thursday, stocks opened sharply lower as growing coronavirus infections and a higher-than-expected initial jobless claims figure further complicated hopes for a swift U.S. economic recovery.
Less than one hour into the new trading day, stocks erased their earlier declines and turned positive.
"Long term I'm bullish," Cramer said. But he added, "I have to stick by, if you haven't taken a little bit off, I think you have to."
In a tweet Wednesday, Cramer further explained his thesis.
"I don't think it's such a bad idea to trim them. They're so big," he said.