Equity markets continue to show "remarkable strength," economist Jeremy Siegel said in his weekly commentary Monday, adding that investors should keep vigilant about Federal Reserve policy on interest rates.
The S&P 500 and other major indexes "are flirting with or surpassing all-time highs," Siegel, WisdomTree senior economist and Wharton School finance emeritus professor, wrote.
"The breadth of the rally is particularly noteworthy, with a growing number of stocks hitting 52-week highs. Small-cap stocks, as represented by the S&P 600, are performing exceptionally well, closing at record levels.
"This breadth is a key signal of market health, as it indicates a robust and inclusive rally rather than one concentrated in a few mega-cap names," Siegel said.