While every presidential race comes with copious speculation over which candidate will be better for stocks, historically who holds control of the government has had very little relevance to the direction of the market, said CNBC. Over decades, whether a Republican or a Democrat is in the White House seems to have had little impact over the value of the S&P 500 in the two years after the election. This is also the case regardless of how many seats the president's party picks up in the House or Senate.

The exception is when the same party controls both the White House and both parts of Congress. In those cases, no matter which party has control, returns are worse; while, historically, Republican control has been a little better than Democratic on this metric, both are outdone significantly when the Congress is split, as markets prefer checks and balances and get uncomfortable when one party has a major advantage over the other. Historically, the best stock market returns have been when there's a Democrat in the White House and Congress is split; the second best returns are when there's a Democratic president and a Republican Congress. But CNBC warned against reading too much into this, as it allows people to shape a historical quirk into a coherent narrative that gives too much significance to which party controls what.

Analyst Tom Lee, of research boutique Fundstrat, quoted by CNBC, believes that this will still hold true now, saying that 90 percent of portfolio strategy will be the same no matter who wins.