When Goldman warned on Friday that a "big drop" in the market is possible before the S&P hits the firm's year end price target of 2,100, one of the bearish reasons brought up by the firm's chief strategist David Kostin is that stocks are now massively overvalued. In fact, according to Goldman , while the aggregate market is more overvalued than 86% of all recorded instances, the median stocks has never been more overvalued, i.e., is in the 100% valuation percentile, according to some key metrics such as Price-to-Earnings growth and EV/sales.
This is what Goldman said:
Valuation is a necessary starting point of any drawdown risk analysis. At 16.7x the forward P/E multiple of the S&P 500 index ranks in the 86th percentile relative to the last 40 years. Most other metrics paint a similar picture of extended valuation. The median stock in the index trades at the 99th percentile of historical valuation on most metrics (see Exhibit 3).
Goldman's conclusion: "The most likely future path of US equities involves a lower valuation."