Illumina campus in San Diego
A sign on Illumina’s campus in San Diego. Reuters/Mike Blake

Activist investor Carl Icahn is preparing a proxy fight at Illumina, arguing that the San Diego biotechnology company’s acquisition of Grail has cost its shareholders roughly $50 billion, the Wall Street Journal reported on Sunday.

Illumina completed a takeover of cancer-detection test maker Grail in August 2021, without securing regulatory approval from the European Union. The European Commission ordered Illumina in December to unwind the deal, three months after it had blocked the merger on concerns the deal would stifle innovation.

Icahn plans to nominate three people to Illumina’s board, the WSJ report said, citing a letter the billionaire plans to send to the shareholders on Monday.

“We are convinced that at least three shareholder representatives are needed on Illumina’s board to attempt to put an end to this insanity now before the reckless decision making escalates into a no-return situation,” Icahn wrote in the letter, according to the WSJ.

Icahn in the letter said his nominees — Vincent Intrieri, the founder and chief executive officer of an investment fund, and two of his deputies Jesse Lynn and Andrew Teno — would bring experience dealing with crises to the board.

Icahn wrote that he tried to strike a deal with Illumina to avoid a proxy battle.

Illumina declined to comment on the report while Carl Icahn did not immediately respond to a Reuters request for comment.