S&P 500 Record Price-to-Sales Ratio is Warning Stock Market Trading on Thin Ice. As the chart below shows, the price-to-sales ratio (P/S) of the S&P 500 is at an all-time high of 2.42. As a result, that’s a major warning sign that the stock market could be in for some rough times. After all that 2.42 is even higher than the previous record of 2.40 ratio at the peak of the dot.com bubble 20-years ago. The fact is that the stock market also is overvalued according to the more popular price-to earnings ratio (P/E). However, we regard the price-to-sales ratio of companies as a far more accurate gauge, therefore, a clearer warning sign, because earnings are subject to all sorts of accounting manipulation. So watch out!