Shipping companies are quick out of the gate to collect refunds for tariffs, even as President Trump begins to apply political pressure for them to forgo the money.

DHL (DHL.DE), FedEx (FDX), and UPS (UPS) have all confirmed plans in recent days to seek refunds of the tariffs they paid over the last year, which were declared illegal by the Supreme Court in February.

“We are beginning to file claims,” FedEx said in a statement to Yahoo Finance.

All three companies are also pairing their requests with promises to pass along the money to their customers.

“DHL Express is committed to helping customers recover IEEPA tariffs they paid,” DHL wrote in its statement. UPS said it was making its requests “on our customers’ behalf.”

For shipping companies, customers have a clear case for refunds, as tariffs are often a line item on shipping invoices.

Read more: What Trump’s tariffs mean for the economy and your wallet

US Customs and Border Protection opened an online portal this week for businesses to apply for refunds, only for Trump to discourage businesses from using it.

He said on Tuesday he would “remember” companies that declined to seek refunds after he was asked in a CNBC interview whether companies like Amazon (AMZN) and Apple (AAPL) might not request refunds for fear of angering him.

“I think it’s brilliant [and] if they don’t do that, I’ll remember them,” the president said.

About $166 billion in tariff collections is eligible to be refunded, and any money will flow to businesses, as only the importers of record can request refunds.

Yet the pressure is mounting for all companies to pass along any refunds they get to customers who paid higher prices because of the duties.

At least 17 lawsuits have been filed against companies, including FedEx, Costco (COST), and UPS, and growing political pressure was also on display on Capitol Hill on Wednesday.

In testimony before the House Ways and Means Committee, US Trade Representative Jamieson Greer was repeatedly pressed by Democrats to ensure the money would make its way to customers.

“Customs and Border Protection is on it, and they have a portal that’s been open for a few days,” Greer said, but he denied that customers are paying higher prices because of tariffs.

Greer was also asked to respond to Trump’s claim in the CNBC interview that refund money is headed to America’s adversaries.

Greer noted that some of the money would be “going back to actually foreign companies … who are unfortunately dependent on China for their supply chains.” But he tried to walk back Trump’s claim that in many cases “the enemy is getting this money”.

Shipping companies like FedEx are also beginning to set up information sites for customers interested in refunds, but with a warning that customers won’t see any money until the government issues refunds to the companies.

“After we receive the funds from CBP, we have established a process to issue refunds to the payors,” UPS said in its notice.

Refund checks are not expected until this summer at the earliest. A previous government estimate suggested the review process for claims may take about 45 days, with checks following 60 to 90 days after approval.

Not all tariffs will be paid back. The Supreme Court ruling in February found that duties based on the 1977 International Emergency Economic Powers Act (IEEPA) were illegal, but the case didn’t address other sector-specific tariffs.

Trump continued to lambaste tariff refunds on Wednesday on Truth Social with a post that called his administration’s requirement to offer refunds “unexplainable” and called the Supreme Court’s decision an “unnecessary and expensive slap in the face to the U.S.A.”

Ben Werschkul is a Washington correspondent for Yahoo Finance.

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