According to the popular «presidential election cycle theory», financial markets tend to decline in the year following a presidential election. (gokinfo.com)
This happens generally every other presidential election cycle, since a president who can run for another term generally does so with their party's support. (politics.stackexchange.com)
Of course, as usual, the usual caveat applies for presidential polling right now: It remains insanely early and we aren't even out of the current presidential election cycle. (nystateofpolitics.com)