If we weight market capitalizations and net earnings for the three S&P categories and then take the ratio, we have a price-earnings ratio of Aggregate earnings and this priceearnings ratio imply an estimate for the aggregate market capitalization of times GNP, which is close to that for industrials only. We should note that an estimate of 19 for the price-earnings ratio is significantly higher than that reported by Fisher, who cites the Standard Statistics Company as the source for his data. Chart 11 of Fisher (1930) shows monthly price-earnings ratios for 45 industrial companies between 1928 and 1929. If we take a 12-month average ending.
