Tulips in 1637, technology stocks in 2000 and US housing in 2007 are examples when bubbles occurred, Bank of America equity strategist Savita Subramanian said, adding that the S&P 500 current level is not comparable.

“Today’s S&P 500 is half as levered, is higher quality and has similar or lower earnings volatility than in prior decades,” Ms Subramanian said in a note. “The index composition has shifted from 70 per cent asset-intensive manufacturing, financials and real estate in 1980 to 50 per cent asset-light innovation-oriented companies today.”