Corteva, Bayer Clash on Corn Royalties Tied to Brazil Patent (1)

Corteva Inc. told Delaware’s top court that Bayer AG is using a Brazilian patent to improperly prolong US royalties on corn-seed sales years after its domestic patents expired.

The Delaware Supreme Court heard arguments Wednesday in a case that could clarify how long companies must keep paying royalties under global patent agreements—especially when US patent rights have lapsed but related foreign patents remain in force.

Corteva argued that requiring US royalty payments after its domestic patents expired raises seed prices for farmers, harms consumers, and violates patent law by depriving the public of the right to freely use expired inventions. ...