The 30-stock index has surged more than 31 percent since Trump's inauguration.
That marks the index's best performance during the first year of a president since Franklin Roosevelt.
"You've got lower taxes, less regulation and confidence in the economy is high," said one investor.
The S&P 500 has surged 23 percent during Trump's first year in office.
There really is nothing stopping the market from going higher at this point. I could see this reaching 40,000 before there is any serious pullback or panic selloff. The one variable that no one can control is the algo trading. If something triggers the algos to sell, then we could see a big drop. Who knows. I invest in Bitcoin, so what I do know.