A wave of dollar selling in Asia is an ominous sign for the greenback as the world’s export powerhouse starts to question a decades-long trend of investing its big trade surpluses in U.S. assets.

Ripples from Friday and Monday’s record rally in the Taiwan dollar are now spreading outward, driving surges for currencies in Singapore, South Korea, Malaysia, China and Hong Kong.

The moves sound a warning for the dollar because they suggest money is moving into Asia at scale and that a key pillar of dollar support is wobbling.