The first wave of tariff refund checks began going out to businesses this week.

Heavy-truck maker Oshkosh Corporation (OSK) and toymaker Basic Fun confirmed receiving partial refunds.

Oshkosh CFO Matt Field said in a statement that the refunds so far represented only “an initial portion of our total claims submitted.”

Jay Foreman, CEO of Basic Fun, said their refunds so far represented just 5% of the company’s total claims.

“So far, the funds are trickling out, but they have started,” Foreman said.

Overall totals for this first wave of refunds weren’t immediately available. The US Customs and Border Protection is managing the process and didn’t immediately respond to Yahoo Finance about the size and number of this first round of payments.

Businesses have been navigating a four-step refund process since a refund portal opened last month. That followed a US Supreme Court decision striking down President Trump’s blanket second-term tariffs imposed under what he deemed an economic emergency. The court said the president didn’t have the power to impose tariffs, but didn’t dictate whether refunds needed to be paid.

WASHINGTON, UNITED STATES - MAY 12: U.S. President Donald Trump speaks to members of the press before boarding Marine One on the South Lawn of the White House in Washington, United States, on May 12, 2026. (Photo by Kyle Mazza/Anadolu via Getty Images)

President Trump speaks to members of the press Tuesday before departing for a visit to Beijing that he suggested will be heavily focused on trade. (Kyle Mazza/Anadolu via Getty Images) · Anadolu via Getty Images

Trump has harshly criticized the ruling since it was handed down in February and has zeroed in on the refunds in recent days. In a radio interview on Tuesday, he said “we’ll fight” the refunds even as his team has moved forward relatively quickly on the refunds themselves.

At stake in total is an estimated $166 billion in tariffs, plus interest, that the government estimates are eligible for refunds.

Also on Tuesday, the Treasury Department’s monthly statement showed that tariff revenue came in at $22.12 billion last month, a slight decrease from March’s reading of $22.15 billion.

Yet that still marks the sixth consecutive monthly decline, to cap a nearly 30% drop from last October, when monthly tariff revenue peaked at $31.35 billion.

Tuesday’s release doesn’t include any of this week’s refunds — those will show up in May numbers.

‘Phase one’ of the tariff refund process

Not all tariffs are eligible during “phase one” of this program, but the government has moved more quickly than many trade experts had expected and promised that “more complex refund scenarios” will eventually be addressed.

Government checks are going to businesses, but those funds could potentially be passed along to consumers. At least 17 lawsuits have reportedly been filed against companies, including FedEx (FDX), Costco (COST), and UPS (UPS), by consumers who say the companies would be wrong to keep any money they get back.

Shipping companies were the first to make a strong tariff refund push, even as Trump applied political pressure on businesses to forgo the money. FedEx, UPS, and DHL (DHL.DE) all paired their requests with promises to pass along the money to their customers.

LAS VEGAS, USA - JANUARY 09: The Oshkosh Corporation booth is seen at CES 2025 in Las Vegas, Nevada, USA, on January 9, 2025. Oshkosh Corporation, an American industrial company, designs and builds specialty trucks, military vehicles, truck bodies, airport fire apparatus, and access equipment. (Photo by Artur Widak/NurPhoto via Getty Images)

The Oshkosh Corporation booth is seen at CES 2025 in Las Vegas in January. (Artur Widak/NurPhoto via Getty Images) · NurPhoto via Getty Images

Basic Fun said its tariff refunds would be used to support our cash flow and invest in personnel, including through increased salaries, new promotions, and larger merit increases.

“We are reinvesting the funds in our business and people,” CEO Foreman said

Tariff landscape continues shifting

Overall, tariff collections have been dropping for months since Trump backed away from a variety of duties last fall — most notably on grocery store items — as fears of tariff-fueled price increases mounted.

In early April, Trump further adjusted tariffs on steel, aluminum, and copper, lowering duties on some goods “substantially made” of these metals, helping contribute to April’s lower number.

Just this week, Trump reportedly planned to suspend some beef tariff quotas in the face of high domestic prices.

Importers are also awaiting the next steps after the Court of International Trade delivered Trump another setback with a ruling that could both invalidate his 10% Section 122 tariffs and require refunds with interest.

The Trump administration on Monday asked the US trade court to pause its ruling, which would mean, in effect, that importers would keep paying the duties as the legal fight plays out.

Ben Werschkul is a Washington correspondent for Yahoo Finance.

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