Wharton School finance professor Jeremy Siegel predicts surging Treasury bonds years will be a challenge to the seemingly endless bull-run stock market for the rest of the year.

“Yields are definitely going to be a challenge to the stock market this quarter,” Siegel told CNBC.

Siegel expects stocks to either level off or dip a bit because if the 10-year yield moves up along with the anticipated Federal Reserve rate hikes, it will be hard for the equity market to make a lot of progress, CNBC.com explained.

“What is the good news? Maybe if they make a deal on China before year-end. That will give you some pop, but other than that I don’t see what could drive stocks markedly higher this quarter,” he said.

To be sure, U.S. stocks headed for the biggest two-day slide since May as the sell-off in technology shares deepened amid growing concern the U.S.-China trade spat will intensify. Treasury yields rose to seven-year highs on speculation the latest jobs report clears the path for raising interest rates, Bloomberg reported.

Just a week after U.S. stocks plowed to fresh records, investors continued to sell the bull market’s biggest winners, ditching high-flyers from Amazon.com to Netflix. The tech rout is the latest blow for global stocks in a week that saw 10-year U.S. Treasury yields climb to to seven-year highs, reducing demand for riskier assets. Fed Chairman Jerome Powell stoked the rates surge when he said the central bank could eventually boost its benchmark past the neutral level.

Siegel isn't alone in his warning about yields continuing to surge.

Jeffrey Gundlach, chief executive of Doubleline Capital, on Thursday said the 30-year U.S. Treasury bond yield has broken above a multiyear base, which should lead to significantly higher yields for financial markets.

“As I have been saying, two consecutive closes above 3.25 percent on the benchmark 30-year Treasury means that my statement in July 2016 that we were seeing the low - I said italicized, underlined and in boldface - is now, looking at the charts, thoroughly corroborated,” Gundlach told Reuters.

“The last man standing was the 30-year, and it has definitively broken above a multiyear base that should over time carry us to significantly higher yields,” Gundlach said. “Also, the curve is steepening a little in this breakout, which is another sign that the situation has changed.”

Gundlach, who manages $123 billion, said the stock market in the United States “has started to take notice, and will continue to, particularly if the speed at which rates rise becomes alarming.”

Gundlach noted that stocks outside the United States are already down significantly from the Jan. 26, 2018, synchronized high, “which will go down in history as the peak for the global stock market for this cycle.”