Antitrust authorities on both sides of the Atlantic reached opposing conclusions about the legality of an acquisition of the developer of a cancer-detection test by a DNA-sequencing supplier. These decisions grapple with several hotly debated issues in antitrust law. The transaction does not involve the horizontal combination of competitors, but rather a vertical acquisition of a customer in an emerging and innovative market, raising concerns that, if the acquisition were not blocked, other current or potential customers—developers of cancer-detection tests—might be foreclosed from access to critical technology. Decision-makers also had to confront the buyer's commitment to solve the concerns by promising not to discriminate against these other customers. Adding further complexity, these merger challenges arose in an unusual procedural posture—especially in Europe, where the transaction did not meet the relevant thresholds for pre-merger notification— because the parties consummated the deal while investigations on both sides of the Atlantic were ongoing.

Illumina, Inc. supplies DNA-sequencing technology used for genetic and genomic analysis. Grail, Inc., is a developer of a multi-cancer early detection test that, along with similar tests still in development, is understood to be groundbreaking in the early detection and treatment of cancer. Illumina formed Grail in 2016 and then spun it off shortly afterwards, while maintaining a minority stake. Illumina agreed to reacquire Grail in September 2020, and the deal was consummated in August 2021.