He was attempting to ease financial markets but Monday's swoon showed he did the opposite.

So then President Trump weighed in by tweet and renewed his criticism of the Federal Reserve. That also did not have the desired effect. Instead of the typical Santa Rally, we saw US investors flee stocks for safety.

Not exactly the Christmas cheer the White House was hoping for.

What does this mean for 2019? A lot will depend on what happens in Washington: government shutdown, simmering trade tensions and the president's tweets.

One thing has been made very clear: if the White House wants to calm nervous investors, it's going to need to get much better at its messaging.