US stocks were mostly unchanged in after-hours trading as results from Tuesday's midterm elections rolled in.

Investors have been betting on a big Republican wave in the elections. If Republicans take at least one chamber of Congress, that will likely result in more gridlock, which the market usually loves. Investors are more than happy when politicians bicker but don't actually enact any new laws that may hurt corporate profits.

Dow futures were down 45 points, or about 0.14%. S&P 500 futures were down 0.1%, and the Nasdaq Composite was down 0.01%.

Early results on election night can be very different from the final outcome once all the votes are tallied. That process can take days.

If Republicans do well and take back control of one or both chambers of Congress, we see the event as a positive for the stock market into year-end, Lori Calvasina, head of US equity strategy at RBC Capital Markets, said in a note to clients on Monday. But if Republicans only take back control of the House, and not the Senate, we suspect the gains in the S&P 500 may be modest.

Since 1948, the S&P 500 has had an annualized return of 16.9% during the nine years when a Democrat was in the White House and Republicans had a majority in both chambers of Congress, according to Edelman Financial Engines. That compares to 15.1% during periods of full Democratic control and 15.9% in years when there was a unified GOP government.

But at the end of the day, political headlines are often just noise for the markets. Ameriprise chief market strategist Anthony Saglimbene said on a conference call last week about the midterms that stocks have historically gone up after elections, no matter which party controls the White House and Congress.

Saglimbene noted that growth, profits, inflation and interest rates matter more to investors over the long haul.