The midterm elections are over (at least, most of them). And an anticipated blue wave turned into a blue tsunami. Democrats picked up commanding majorities in both the U.S. House of Representatives and the U.S. Senate.

Every two years, some investors look to Washington, D.C. to decide how to recalibrate their portfolios based on who is in power. What does a new Democratic-controlled Congress in January mean for your investing strategy?

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What history shows

If history is any guide, investors could be in for some good news. Since 1950, the S&P 500 (^GSPC -0.40%) has been higher 12 months following a midterm election 100% of the time. That’s right: in 19 midterm elections over the past 76 years, the S&P 500 has…