Logistics firms are scrambling to adjust to President Donald Trump’s new rules that threaten to upend their booming business delivering small parcels from Chinese sellers to American buyers.

His decision to revoke a “de minimis” rule for China, effectively closing a loophole that allowed small packages under $800 to enter the U.S. duty-free, took effect just after midnight February 4, Washington time, affecting the billions in goods sold by retailers like Shein and Temu.

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The initial impact has been confusion and hurried efforts by some logistics firms in China to raise prices to get in front of higher tariffs. But Trump’s move risks far-reaching consequences, including squeezing U.S. consumers already struggling with cost-of-living stress.

While China officially reported about $23 billion worth of small parcel exports to the U.S. last year, Nomura Holdings Inc. estimates as much as $46 billion of U.S.-bound packages came from the country. The de minimis revocation could cut China’s export growth by 1.3%, and reduce its gross domestic product expansion this year by 0.2%, the bank said, adding to existing challenges already weighing on the world’s second-biggest economy.

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Trump’s orders have also highlighted the complex supply chain that underpins the flow of packages. Most small parcels — about 50% of the international direct mailing services market, according to China Merchants Bank Co. — are sent via air or sea through national postal carriers like the U.S. Postal Service. That’s why the USPS’s flip flop on transporting goods from China and Hong Kong unnerved the industry.

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The method is typically cheap, but it takes two to three weeks for goods to be delivered. The second-most popular option, accounting for roughly 40% of the market, is to use air cargo services arranged by logistics agents, which usually cost more but boast delivery times of about a week. The most expensive option, accounting for 10% of the market, is to send parcels via plane through the likes of FedEx Corp., United Parcel Service Inc., DHL and China’s SF Holding Co. 

Here’s a look at how the sector’s key players are impacted:

Hongkong Post

The financial hub’s postal service said it won’t accept parcels to the U.S. until further notice. The operator said it had started talks with USPS, but there are matters requiring further clarification, including tariffs. 

USPS

The USPS said it’s accepting “all international inbound mail and packages” from China and Hong Kong, and is working with U.S. Customs and Border Protection to minimize delivery disruptions. It’s also implementing a collection mechanism to ensure new tariffs are charged and collected.

FedEx

FedEx said it was working with, and supporting, its customers as it adapts to substantial changes from the tariff announcements. Shipments continue to move between the U.S. and China, according to a spokeswoman, who declined to comment on whether the company had adjusted its flight schedules or delivery times for U.S.-bound packages from China.

UPS

The company said it will continue to provide service into and out of China and Hong Kong.DHLDHL Asia Pacific said there may be additional time and fees involved in sending items. The company has not suspended handling packages from Hong Kong that are destined for the U.S.

SF Express

The major logistics provider in China raised the clearing fee and tariff deposits for U.S.-bound small parcels, according to Nomura. All e-commerce packages shipped from China are subject to additional clearing fee of 20 yuan ($2.70), as well as a pre-collection of 30% tariff deposit based on the package’s weight, the bank said.

Shein, Temu

Chinese retailers that sell on Shein and Temu platform say they have been asked by logistics agents to start paying an additional 30% levy.

The vendors received notifications about the new prices they would be charged by their logistics agents late on the night of February 5, according to a memo seen by Bloomberg. The extra 30% of the retail value of the goods being sold must be paid in the form of a deposit, which agents will then return or ask to be topped up depending on the actual tax charges from U.S. customs.