A new government portal went live Monday morning, allowing businesses to begin requesting refunds for the blanket tariffs struck down by the US Supreme Court.

The CAPE portal, an acronym for Consolidated Administration and Processing of Entries, is being run through an existing government system that manages tariff duties and will now allow companies to apply for refunds after the government confirmed last week that initial development of the program had been completed.

“CAPE is designed to consolidate refunds of IEEPA duties including interest rather than processing refunds on an entry-by-entry basis,” US Customs and Border Protection wrote in a release.

Monday’s launch could mark a major moment for US importers who have been seeking clarity in the weeks since the US high court struck down the duties but didn’t weigh in on the details of a refund process.

Not all of the estimated $166 billion in illegally collected tariffs, plus interest, will be eligible for refunds during “phase one” of this program, but the government has promised more phases are coming for “more complex refund scenarios,” signaling that a wide array of tariff refunds will eventually be offered.

Read more: The latest news and updates on Trump’s tariffs

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

Read more: 5 ways to tariff-proof your finances

Some groups have been helping navigate the process, with the Main Street Alliance offering words of caution Monday around the launch.

“While the launch of the refund process is an important milestone, significant challenges remain,” the group said in a statement as it pushed the Trump administration to streamline the process, arguing that a “complex claims process” ahead may be too burdensome for many businesses.

The portal launched on Monday is part of a four-step process for businesses to claim refunds. Only businesses that actually paid tariffs can claim refunds, but multiple consumer lawsuits have been filed demanding that refunds be passed on directly 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.

The refund process kicks off two months after the Supreme Court, in a 6-3 decision, halted a central piece of President Trump’s tariff agenda announced last year on “Liberation Day” with duties based on the International Emergency Economic Powers Act (IEEPA).