It has been a difficult year for meat consumers. The New World screwworm, a flesh-eating parasite originating from Mexico, has caused dozens of confirmed livestock infestations. Drought is affecting 75% of all livestock in the country and has driven cow herds to a 75-year low. Combined with tariffs on Brazil, the world's largest beef exporter, these pressures pushed the average price of a pound of ground beef to $6.89 in July, up 10% from a year earlier.

The Department of Justice now wants to know whether eight of the country's largest grocery retailers can be blamed.

Federal investigators are scrutinizing Walmart, Costco, Amazon, Kroger, Publix, Albertsons, Aldi and Ahold Delhaize USA over beef affordability. Together, these chains account for a large share of U.S. grocery sales, a market that has consolidated over decades and drawn antitrust attention before—most recently in the FTC's challenge to the proposed Kroger-Albertsons merger, which the retailers abandoned in 2024 after courts blocked it. The DOJ called beef prices a "priority" for the agency in a Sept. 1 X post announcing the probe. The retailers and the DOJ did not respond to Fortune's requests for comment.

The Trump administration has zeroed in on tamping down beef prices, as the cost of staples like ground beef shapes how consumers judge inflation—a key issue for voters ahead of the midterm elections.

The new probe into retailers appears to build on the department's antitrust investigation into meatpackers launched in May. It also echoes earlier federal scrutiny of the beef supply chain: the DOJ opened a price-fixing investigation into meatpackers during the pandemic-era disruptions of 2020, and the USDA has long policed the sector under the century-old Packers and Stockyards Act.

Trump asked the DOJ to probe meatpackers over beef prices in November, accusing them of "driving up the price of Beef through Illicit Collusion, Price Fixing, and Price Manipulation." He scrapped 40% tariffs on Brazilian beef the same month, and announced last month a plan to allow 300,000 metric tons of it into the country without being subject to out-of-quota tariffs.

The administration has also tried other ways to ease prices. It began importing beef from Argentina, drawing backlash from American ranchers who said the move would introduce disease risks to domestic cattle and do little for grocery prices. The administration also started allowing some imports of Mexican livestock back in on Aug. 24, after having barred them in July when Mexican cattle tested positive for screwworm.

Meanwhile, the meatpackers have struggled financially. Tyson announced on Aug. 13 that it is closing two beef plants and selling a third, a week after reporting a $138 million operating loss in its beef segment. JBS, headquartered in Brazil, halted beef processing at its Pennsylvania plant a day after Tyson's announcement, having reported a $279 million adjusted operating loss for its North American beef business.

Trump announced last week that he is allowing ranchers to process meat themselves, but it is unclear how he plans to alter meat processing regulations. Ranchers can process their own meat for personal use but cannot sell it unless it meets strict safety and sanitation standards and undergoes inspections.

Other factors driving up beef prices

Herd size is a major factor in making beef costlier. Farmers had 86.2 million cattle and calves at the start of this year, the lowest number since 1951, according to data from the U.S. Department of Agriculture. The costs of maintaining a herd—feed, fertilizer and equipment—have risen as a result of tariffs and drought, so fewer farmers breed cows for slaughter, which restricts beef supply.

While cow-calf ranchers, who supply cows for the entire industry, are able to raise prices and mint fortunes, other farmers are stuck buying more expensive cattle and face slimming margins.

Another hurdle is the time it takes for cows to reproduce and be ready for slaughter. Heifers are bred from between 12 to 15 months of age, and calves have a gestation period of just under a year before staying up to 10 months with their mothers. Farmers then face the choice between keeping calves as breeding stock to rebuild the herd or sending them to beef production.

But farmers know this biological cycle and can manage it without market interference.

"They're not asking for anything," Derrell Peel, a professor of agribusiness specializing in livestock at Oklahoma State University, told Fortune last year. "Basically, they just want everybody to get out of the market and let it do what it does."

This story was originally featured on Fortune.com.