Ahead of President Trump’s next big trade move, his administration invited companies to weigh in on the economic barriers they faced abroad.

The list of complaints was both sprawling and specific. In hundreds of letters submitted to the administration in recent weeks, producers of uranium, shrimp, T-shirts and steel highlighted the unfair trade treatment they faced, in hopes of bending the president’s trade agenda in their favor. The complaints varied from Brazil’s high tariffs on ethanol and pet food, to India’s high levies on almonds and pecans, to Japan’s longstanding barriers to American potatoes.

Mr. Trump has promised to overhaul the global trading system on April 2, when he plans to impose what he is calling “reciprocal tariffs” that will match the levies and other policies that countries impose on American exports. The president has taken to calling this “liberation day,” arguing that it will end years of other countries “ripping us off.”

“It’s a liberation day for our country, because we’re going to be getting back a lot of the wealth that we so foolishly gave up to other countries,” Mr. Trump said last week.

The president had floated the idea of also announcing sector-specific tariffs on cars, pharmaceuticals and semiconductors that same day. On Monday, White House officials said that those additional tariffs had not yet been set for April 2 but that the situation remained very fluid.

One official said that separate tariffs on cars could still happen on April 2. Another official said that if tariffs on cars and other sectors did not happen on April 2, they could still be imposed at a later date.

Markets opened higher on Monday after Bloomberg and The Wall Street Journal reported that the White House was not likely to announce industry-specific tariffs on April 2.

Still, the price of imported cars, medicines and semiconductors will probably go up through Mr. Trump’s reciprocal tariff plan. Many details of that plan remain unclear, but administration officials have indicated that the reciprocal tariffs would add an additional fee on top of most or all products imported from specific countries.

It’s not clear how many countries will be hit, but Trump officials have mentioned the “dirty 15,” a reference to a group of countries that have tariffs on American products and run trade surpluses with the United States, presumably including most of America’s largest trading partners.

The reciprocal tariff plan has created a tricky calculus for many companies, which want to see trade barriers erased but fear ending up at the center of a trade war that could make them worse off. That is because Mr. Trump’s high-stakes approach could generate efforts by other countries to make deals with the United States and drop their own tariffs — or it could invite retaliation that ends up closing off foreign markets to American products.

Some American companies see an opportunity in Mr. Trump’s agenda. Many of the letters that companies submitted to the Office of the United States Trade Representative in recent weeks asked officials to fight for lower trade barriers on their behalf, highlighting the high levies, onerous inspections or other complications American exporters face in foreign markets.

But others appear hesitant to put themselves in the president’s cross hairs. Some industry representatives say privately that companies have been nervous that raising their hands for help could put them at the center of coming trade spats, disrupting the export markets they depend on and potentially making them a target for retaliation.

Publicly, many of America’s biggest exporters — like the trade groups that represent exporters of pork, soybeans and oil — tempered their filings with cautionary words about the harm that could come from disrupting export markets. Major business groups also continued to urge the administration to reduce trade barriers rather than raise them, and focus on striking new trade agreements that would open up foreign markets.

“The administration’s work on reciprocity should result in the removal, not the creation, of barriers to trade,” the Consumer Technology Association, which represents technology companies, said in its letter to trade representative. The group said it was “deeply concerned” that tariff threats against Europe would “increase global barriers to trade and dismantle the global trading system.”

Other groups seemed to be aware that the information they were handing the Trump administration could become ammunition in a trade war in which they could be casualties. The U.S. Chamber of Commerce said the information it was submitting on trade barriers was “not intended to justify the application of broad-based tariffs but should help U.S. negotiators to focus on specific issues of importance to American businesses of all sizes.”

It remains to be seen whether these submissions will have much influence over Mr. Trump, who has a history of basing trade policy on his impulses and intuition. But the quantity and variety of the responses highlight the enormous challenge for the Trump administration as it tries to figure out how to put its own imprint on the global trading system with just a few weeks of preparation. And it hints at the controversy that may be awaiting the administration once it finally reveals the details of a still-ill-defined trade policy.

Mr. Trump has suggested that his forthcoming tariffs could be sweeping and influential. But for now, even the basic question of whether the administration’s efforts will result in higher or lower barriers to trade remains unanswered.

The president has said his guiding principle is reciprocity. If other countries charge the United States high tariffs or install other economic barriers, the United States will mirror that treatment for their exports, he said. Mr. Trump has often mentioned India’s high tariffs on motorcycles, Europe’s tariffs on cars and its value-added tax, and Canada’s protections for its dairy market.

Treasury Secretary Scott Bessent said last week that the administration planned to come up with a tariff number for each country that it would impose on April 2. That number would represent the levies that foreign governments imposed on American products along with other barriers, like taxes.

Mr. Bessent said some countries might be able to pre-negotiate deals and not face additional tariffs. Officials in Britain, India, Mexico, the Europe Union and elsewhere have been angling for such an outcome, though some are also drawing up lists of retaliatory tariffs if Mr. Trump moves forward.

It also remains uncertain exactly what the president wants the reciprocal tariffs to accomplish. Mr. Trump’s administration has cited a litany of reasons for his tariffs, including making trade more fair for American exporters, eliminating trade deficits with other nations and generating more tariff revenue to finance his tax cuts.

With these goals still unclear, some companies are trying to shape the agenda. Many of the submissions to the trade representative pointed to China as a primary threat, with companies highlighting the risk that cheap Chinese imports pose to various U.S. industries.

Makers of American flags and Jacuzzis complained that competition from China was threatening to put them out of business. American Christmas tree growers argued that tariffs on artificial Christmas trees from China would help U.S. tree farms. The poultry industry criticized Chinese barriers to the sale of U.S. chicken parts, including chicken feet and wing tips.

But plenty of other countries were mentioned as well. Makers of catfish and prunes complained of Vietnam’s trade barriers. Corn growers cited Mexico’s recent ban on genetically modified corn. J.M. Smucker called out Europe’s tariffs on jam and jelly, while Chobani criticized Canada’s barriers to yogurt imports.

Nearly two dozen entries alone highlighted the dire situation of the American shrimp industry. The Louisiana Shrimp Association called for a quota or other limits on shrimp imports, saying foreign shrimp had depressed prices so much that shrimpers could not even afford to fire up their boats.

“The volume of cheap, possibly contaminated shrimp has put the domestic shrimp industry in a downward spiral,” George Barisich, a 69-year-old shrimper from Louisiana, wrote in a letter. “Last year, I received one-third of the price for shrimp that I got in the 1980s.”

Some called for the U.S. government to distinguish between different parts of the world. Medical manufacturers argued for protection from China but cautioned against hitting America’s closest allies, saying that could have unintended negative consequences.

The tool maker Stanley Black & Decker said that it had worked to trim its imports from China to around 15 percent in 2025 — from around 40 percent in 2018 — and that it should not be penalized for moving its supply chains to Mexico.

“Companies like ours that are doing the right thing and leaving China should be acknowledged,” the company said.

Many industry groups also sent letters arguing against tariffs on products that are not made in the United States, saying import taxes on spices, coffee and Christmas decorations would simply raise prices for American consumers.

America’s major export industries, such as corn, pork, oil and soybeans, highlighted some global barriers but also urged the Trump administration not to damage the export markets that their sales depend on.

Tyson Foods said negotiating new trade agreements was important to avoid falling behind other countries, while the National Milk Producers Federation said dairy exporters were operating at a disadvantage to foreign competitors because the United States had not kept up with the European Union and New Zealand in inking new trade deals.

The filings also contained a reminder that the legacy of trade wars can be long lasting. Some of the barriers that companies complained about — like China’s high tariff on cranberries or a European tariff on peanut butter — were the result of Mr. Trump’s first-term trade wars, in which countries retaliated against tariffs he had levied on them.

Even Tesla, whose chief executive, Elon Musk, is helping to drive much of the president’s strategy, warned of the negative effects that tariffs and retaliation could have on its business. The company noted that past U.S. trade actions had prompted increased levies on American electric vehicles.

“U.S. exporters are inherently exposed to disproportionate impacts when other countries respond to U.S. trade actions,” Tesla said.

Harley-Davidson, the motorcycle maker that Mr. Trump has frequently cited when talking about reciprocity, said it was now facing a 25 percent retaliatory tariff that Canada imposed this month in response to U.S. levies. It also warned about a 50 percent European tariff on motorcycles that had been suspended but could snap back into place.

“Harley-Davison has become a political target,” the company said. “This use of our brand in trade wars unrelated to our sector is unacceptable.”