Both of the China-founded sites say U.S. customers will see higher prices starting next week, and industry data shows they're pulling back on U.S. advertising, too.

The de minimis loophole, which allowed shipments less than $800 to be exempted from tariffs, is slated to end as of May 2.

Both fast fashion giants announced on April 16 that U.S. consumers will feel the impact of Trump's tariffs sooner than they thought.