Although the Flow of Funds data are available only after 1945, it is clear from Figure 3 that the market value of NYSE companies as a fraction of the market value of all . companies has been remarkably constant. The total market value of all domestic corporations is about times the market value of NYSE companies. Notice that these values are very close for the entire post-World War II period — not only on average but at peaks and troughs too. If we assume that the ratio is roughly in the pre-World War II period as well, we can use the NYSE values to.
