The duty on small parcels, previously exempt from duties as part of the de diminis rule, will be increased to US$75 from the US$25 that Trump had set as part of his original opening salvo in the trade war on April 2.
The new US$75 duty will take effect on parcels sent from May 2 and before June 1, which was the period when the original US$25 levy was to come into play. That US$25 levy was originally set to be increased to US$50 after June 1.
An amendment to the so-called reciprocal tariffs published by the White House on Wednesday Hong Kong time said the new rate on packages priced up to US$800 will be 90 percent of their value, up from the original 30 percent.
With the amendment, the per postal item fee will also be tripled to US$150 from the planned US$50 that was to go into effect after June 1.
The new tariff came into play as Trump made good on his punitive measure against China after it had reciprocated his 34 percent tariffs by a similar quantum.
That brought his latest tariffs to 84 percent, making the total, on top of the 20 percent in levies imposed in February and March, 104 percent.
The punitive tariffs come as around 60 percent of all de minimis packages entering the United States come from China.