Bayer Faces New Antitrust Headwinds in US Corn Seed Market as Pharma Pipeline Shows Quiet Progress

Bayer shares hover near €37.90 as a fresh class-action antitrust lawsuit over GM corn traits offsets positive pharma pipeline news and Q1 revenue growth.

Bayer’s stock is treading water at around €37.90, barely budging on the day despite a flurry of corporate developments that cut in opposite directions. The shares have slipped 3.6% over the past week and remain 23% below their February high, caught between a fresh legal assault on its crop-science division and incremental gains in its oncology pipeline.

The latest legal headache lands in the Eastern District of Missouri, where family-owned seed company Latham Quality has filed a proposed class action accusing Bayer of antitrust violations in the US market for genetically modified corn. At the heart of the suit is the NK603 trait, which renders maize resistant to Roundup. The plaintiffs argue that Bayer blocked competitors from developing generic versions after the patent expired in 2022, effectively maintaining a monopoly over a trait found in nearly all GM hybrid corn seeds in the country. Named defendants include Bayer AG, Bayer CropScience LLC, Channel Bio LLC, and Monsanto Co. The company has dismissed the allegations as unfounded and pledged to fight them in court.

The Missouri case is not the only antitrust scrutiny Bayer faces. In late May, the US Department of Justice reported that Bayer had voluntarily removed potentially anticompetitive clauses from its "Premier Performance Program," a loyalty scheme that tied rebates for independent seed distributors to sales targets for corn and soybeans. The DOJ expressed concerns about the bundling arrangement, and Bayer committed not to reintroduce the contested provisions for seven years.

On the pharma side, Bayer is taking a measured step to broaden its oncology portfolio through a research collaboration with Olema Pharmaceuticals. The two companies will launch a Phase 1b/2 trial involving around 36 patients with metastatic castration-resistant prostate cancer, testing Olema’s experimental therapy OP-3136 in combination with Bayer’s established prostate cancer drug Nubeqa. Olema will conduct the study and supply the investigational agent, while Bayer provides Nubeqa. All global marketing and exclusivity rights for OP-3136 remain with Olema. The trial targets patients who have exhausted existing treatments, a niche where drugmakers are eager to extend the utility of their molecules.

Separately, Bayer’s kidney drug Kerendia received approval for an additional indication in China, strengthening its foothold in one of Asia’s most important pharmaceutical markets.

The operational backdrop remains solid. In the first quarter, Bayer posted group revenue of €13.4 billion, a currency- and portfolio-adjusted increase of 4.1%. Earnings before interest, taxes, depreciation, and amortization, adjusted for special items, rose 9.0% to €4.5 billion. The crop-science segment, despite legal clouds, was a bright spot: segment revenue climbed 6.8% to €7.558 billion, with corn seed and traits alone up 7.1%. Adjusted EBITDA in the division jumped 17.9% to €3.014 billion. Yet the legal machinery continues to drain cash: free cash flow came in at negative €2.320 billion for the quarter.

That cash drag reflects the broader overhang from legacy litigation. Reports of constitutional concerns surrounding a proposed $7.25 billion US settlement, combined with mounting efforts in Brazil to restrict glyphosate, keep sentiment in check. Analysts are watching the next catalyst: second-quarter results due on August 4, 2026, with consensus forecasting adjusted earnings per share of €4.37 for the full year. For now, the stock remains pinned between a solid quarterly operating performance and a legal fog that shows no signs of clearing.