The only certainty about Donald Trump's second U.S. Presidency looked to be uncertainty for investors after he went easier than expected on China in his first day back in the job, but then warned Mexico and Canada they faced 25% tariffs from next month.

Chinese markets were relieved after Beijing avoided an instant blizzard of executive orders but Mexico's peso and Canada's dollar weren't so lucky as Trump's off-the-cuff talk about tariffs on both countries from Feb. 1 ensured their currencies both took a tumble.

After his inauguration on Monday, the new U.S. president also floated the idea of universal tariffs, but said the U.S. was not ready for that yet.