Lest I start sounding like a bull market shill, let's take a look at the historical numbers for the third year of the Presidential cycle.
Mr. Yardeni notes that the S&P 500 is up 3.9% since the mid-term elections and is up 5.1% in December. “History suggests that a gain of 20% is likely be the end of next year.”
...
Lastly, since 1962, the stock market has always risen from the mid-term elections through the end of the third presidential year – averaging 20.9%.
Link from WSJ.
so, if we are repeating history, or closely rhyming, it will be difficult to add to returns by market timing. If the goal of market timing or reallocation is to avoid the dips and take more risk on weakness, when the market moves straight up you don't have many chances to do this. And if you try, you may miss some of it.
Hmm. Something to think about.