Caterpillar and Deere stock fell Wednesday after the federal government launched a public inquiry into the farm equipment and distribution industry.

The Federal Trade Commission and the Department of Agriculture said Wednesday they are requesting information from the public "regarding issues affecting agricultural equipment manufacturing and distribution markets, including potential anticompetitive conduct."

Shares of Deere fell 3.3% to $660.17 on Wednesday, while Caterpillar dropped 5.9% to $812.73. Caterpillar stock was the session's worst performer in the Dow Jones Industrial Average, which declined 0.6.%.

The inquiry calls for information on business models, contract terms, and other issues that might affect market pricing. It aims to address "the growing number of complaints received by USDA that farmers across the country face other barriers to acquiring agricultural equipment and the services required to keep equipment operating," according to the news release.

Caterpillar and Deere didn't immediately respond to a request to comment.

The callout for public comment is part of the FTC's continued effort to maintain competition in the agricultural sector, the release said. Earlier this year, the FTC and several states reached a settlement with Deere; their lawsuit alleged that Deere had unlawfully restricted farmers and independent repair shops' ability to repair irs farm equipment. Deere granted full diagnostic software capabilities to independent repair shops as part of the settlement, the FTC said at the time.

Further regulatory action against Deere could spell trouble for its high-margin software business.

Over the past decade, the company has expanded outside its traditional physical tractor business. Deere has become more of a high-margin agriculture-tech company, selling subscription software such as automated steering and artificial-intelligence crop spraying.

Ramifications for Caterpillar, however, will likely be minimal. While its machinery fleets use digital diagnostics and proprietary software, Caterpillar's core revenue engine hasn't relied as much on its its software subscriptions as Deere has.