Another way to detect market tops besides the S&P GAAP PE Ratio is the percent of S&P 500 stocks above their 50 day moving average. The upper chart below is a two year line chart on a weekly time frame showing percent of S&P stocks above their 50 day moving average and the lower chart is the S&P index in weekly bars.
If you look at the top chart and note each time the percent above 50 reaches the top red line, that point corresponds directly with a market sell off beginning in the S&P chart below. The eight above 50 percent peaks in the top chart produced the eight market rollovers shown with red marks on the S&P chart. The eighth one is where we are right now.
Bulls should be very careful here.
Trade well my friends
Alan