When the Equity Premium Was New

In 1924, Edgar Lawrence Smith published an empirical study showing that an equity premium had been consistently realized in history. The now-familiar idea that stocks will outperform bonds over the long run was at that time a startling rejection of conventional wisdom. Smith’s contemporaries expected bonds to have outperformed under the deflationary conditions that prevailed in the later 19th century. Using recently compiled data, I revisit the question of whether history shows an unconditioned equity premium. US and UK data show the historical equity premium to be contingent on the absence of deflation. US and Japan data show that disinflation has effects similar to deflation. The paper concludes by developing the implications of accepting a contingent equity premium.