Cigna defended the deal, saying it would "create tremendous value for shareholders, accelerate the transformation of healthcare and address the dynamic regulatory environment for health services."
"Mr. Icahn, on the other hand, has made a speculative financial bet against the transaction in the hopes that he can create a gain at the expense of Cigna and Express Scripts shareholders. Mr. Icahn's opposition is misguided and short-sighted," Cigna said in a statement.
Earlier, the billionaire investor urged Cigna shareholders to vote against the proposed merger with the pharmacy benefit manager. Icahn, who has a 0.56 percent stake in Cigna, argued that "Cigna is dramatically overpaying for a highly challenged Express Scripts that is facing existential risks on several fronts."
He asserted that those headwinds include competition from Amazon and potential regulatory changes to the rebate system that could affect the company's profitability. Icahn proposed that Cigna "pursue a multi-year partnership with an existing PBM provider, potentially Express Scripts," instead of acquiring the company outright.
Cigna said Icahn "does not represent the interests of Cigna shareholders" and that his opposition "demonstrates a complete lack of understanding of Cigna's business model." The company pushed back on Icahn's belief that rebate regulatory changes would be detrimental to Express Scripts' business. Cigna said phasing out Medicare rebates would not have a material impact on the PBM's earnings.
The company also rejected Icahn's suggestion to pursue a partnership with Express Scripts, saying "It would be exceedingly difficult to draft a static contract that benefits Cigna in all scenarios in a changing environment."
Cigna said the goal of the merger is to increase the reach of both companies by integrating their services, ultimately leading to "immediate and long-term value" for shareholders. The merger "broadens capabilities and distribution for more than 100 million combined customers and deepens data and insights to improve predictability and deliver better health outcomes," the company said.
Shareholders are scheduled to vote on the proposed merger on August 24.