New Antitrust Lawsuit in US Corn Seeds Piles Pressure on Bayer’s Pipeline Progress

Bayer’s shares ended last week in the red despite promising oncology data from the ASCO congress, as a freshly filed antitrust suit in the United States added to the legal overhang already weighing on the stock. The contrasting news flow — a class-action claim over alleged monopolisation of a genetically modified corn trait versus a strong clinical showing for prostate cancer drug NUBEQA — leaves investors parsing which narrative will drive sentiment in the weeks ahead.

The lawsuit, brought by Iowa-based seed company Latham Quality in the Eastern District Court of Missouri, accuses Bayer of illegally dominating the US market for maize containing the NK603 trait. That trait’s last patent expired in 2022, after which competition should have driven prices lower, the complaint argues. Instead, Latham alleges that Bayer prevented independent seed developers from producing generic alternatives and continued collecting royalties beyond the patent term. The claim seeks class-action status and treble damages. Bayer has denied the allegations, insisting the market remains competitive and fair.

The civil action follows closely on the heels of governmental scrutiny. On 20 May 2026, the US Department of Justice announced that Bayer CropScience had voluntarily removed certain clauses from its loyalty programme amid an ongoing DOJ investigation into potential exclusionary conduct in the corn and soybean seed markets. Bayer also committed not to reintroduce those provisions for seven years. While the Latham case and the DOJ probe are technically separate, they converge on the same core issue: competition, licensing and market access in the US seed sector — a business that accounted for roughly 48 percent of Bayer’s group revenue, according to MarketScreener.

Should investors sell immediately? Or is it worth buying Bayer?

On the pharma side, Bayer delivered a clear win at the American Society of Clinical Oncology meeting. Data from the Phase II ARACOG study showed that NUBEQA caused significantly less cognitive decline than the established rival enzalutamide. After 24 weeks, the cognitive drop under NUBEQA was just 15.8 percent versus 36.1 percent for enzalutamide — a highly significant difference (p=0.009). Notably, all 23 patients who switched therapy because of cognitive deterioration moved from enzalutamide to NUBEQA. Bayer develops the drug jointly with Orion.

The market shrugged off the ASCO catalyst, however. Bayer’s stock closed on Friday at €36.48, down 3.57 percent on the day and roughly 5 percent lower on the week. That leaves the shares some 6 percent below the 50-day moving average of €38.73 and a hefty 26 percent under the February 52-week high. Of the 14 analysts covering Bayer, the average recommendation is “Buy” with a price target of €49.47 — implying theoretical upside of about 36 percent.

With the new trading week under way, attention will focus on whether the Latham lawsuit is priced as an isolated event or as evidence of a deeper structural competition problem inside Crop Science. Immediate support sits at €36.30; a decisive break below that level would be taken as a negative technical signal. Meanwhile, the ASCO data could offer a counterweight if investors begin to factor in NUBEQA’s potential commercial edge, but for now, the legal cloud in the seed business looks set to dominate the near-term mood.

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