Jeremy Grantham suggests that current market conditions, with low unemployment, high profit margins, and the Shiller P/E ratio in the top 1% historically, are the opposite of typical bull market beginnings, implying potential for a downturn.
"The legendary investor Jeremy Grantham also seconds him by saying that prolonged bull markets typically begin when unemployment is high profit margins are depressed and stock valuations are beaten down current conditions are the polar opposite of that especially when the Shiller price to earnings ratio is within the top 1% of its historical range."