The people who bet on the stock market know that Trump is good for business. The day after the election, health care stocks soared. They know that Trump is a keen, skilled businessman. They know that he is the first President who is truly going to get out of the way for business.
With the amount of consumer confidence through the Trump election going up the stock market has reached a new milestone. It is very possible that this will continue for quite a while. It may not all be good news though because eventually this energy will fall and the economy might be devastated because of this.
Individual investors often have a weakness for joining a stock market lucky streak just when it is peaking, rather than when it is building. Since the stock market often reacts to emotion, rather than facts, this streak is likely due to current political turmoil in the United States. The rest of the world economy is not doing particularly well, making it more likely that this streak will end soon after the inauguration.
The DOW is only going up in anticipation in a change in leadership. There is a sense that the new administration will let business go without much oversight. It may be good for Wall Street, but it will most likely not be good for the rest of America or even the world.