Shares of the four largest U.S.-listed farm and construction equipment makers — Deere & Company (DE), CNH Industrial (CNH), Caterpillar (CAT) and AGCO (AGCO) — fell after a joint inquiry by the Federal Trade Commission and the U.S. Department of Agriculture put farm equipment market practices under federal scrutiny.

The stock slump came as the two agencies turned their attention to how the equipment sector operates, a signal that manufacturers' commercial practices toward farmers and dealers could face formal review at the intersection of antitrust and agricultural policy.

Why are FTC and USDA acting together?

The pairing matters. The FTC enforces competition law, while the USDA sets and administers farm policy. A joint inquiry lets both agencies examine the equipment market from the antitrust side and from the standpoint of farmer input costs — machinery being one of the largest capital line items in row-crop budgets.

For growers, the focus is straightforward: the cost and terms of acquiring, servicing and repairing machinery directly affect per-acre fixed costs and, ultimately, operating margins when commodity prices are under pressure.

Which companies are affected?

The market reaction hit across the sector:

• Deere & Company (DE) — the largest U.S. farm equipment manufacturer;
• CNH Industrial (CNH) — maker of Case IH and New Holland machinery;
• Caterpillar (CAT) — heavy equipment with a broad construction and agriculture footprint;
• AGCO (AGCO) — owner of Fendt, Massey Ferguson and Challenger brands.

All four traded lower as investors weighed the prospect of heightened regulatory oversight of the industry's market practices.

What does the inquiry mean for farm margins?

Any examination of equipment market conduct touches the cost side of the farm ledger directly. Machinery purchases and service contracts are among the biggest discretionary capital expenditures producers make each cycle, and scrutiny of how those markets function could influence pricing, parts availability and repair options across dealer networks.

Whether the inquiry leads to formal action, settlements or policy recommendations remains to be seen. For now, the immediate effect is financial: a sector-wide share price decline among the four major manufacturers as Washington signals interest in how the farm equipment business conducts itself.

Investors and farm groups alike will watch for the inquiry's scope, any document requests to manufacturers, and whether the agencies convert their review into enforcement — outcomes that would shape both equipment pricing and dealer economics for seasons to come.