Monthly Returns During Presidential and Congressional Election Years

Do hopes and fears of election outcomes in the U.S. affect the "normal" seasonal variation in monthly stock market returns? To check, we compare average returns and variabilities (standard deviations of returns) by calendar month for the Dow Jones Industrial Average (DJIA) during years with and without quadrennial U.S. presidential elections and biennial congressional elections. Using monthly closes for the DJIA over the period October 1928 through May 2019 (nearly 91 years), we find that: