And just last month, the supermarket operator Albertsons said it would buy the remnants of the Rite Aid drugstore chain, in a bet that increased foot traffic from in-store pharmacies would drive more consumers to its stores to shop for other items.
Rite Aid itself had tried to bulk up its operations by merging with Walgreens, but negotiations ended after antitrust authorities indicated that they were unlikely to approve the combination last year. Instead, Rite Aid agreed last year to sell nearly 2,000 stores and three distribution centers to Walgreens.
Express Scripts, based in St. Louis, provides services to company-provided health plans like negotiating drug prices and arranging home delivery of some prescriptions. The company reported revenue of $100.3 billion in 2016 and employed about 25,000 people.
Under the terms of the deal, Express Scripts shareholders would receive $48.75 in cash and 0.2434 of a share of the combined company. That represented a 31 percent premium to the closing price of Express Scripts on Wednesday. Express Scripts was up 14 percent in premarket trading on Thursday.
After the transaction, Cigna shareholders will own about 64 percent of the combined company, and Express Scripts shareholders would own the rest. The transaction is expected to close by the end of the year and is subject to shareholder and regulatory approval.
The combined company would be named Cigna and would be based in Bloomfield, Conn., where Cigna currently has its headquarters. Express Scripts would continue to have its headquarters in St. Louis.
Mr. Cordani would serve as president and chief executive of the combined company, while Tim Wentworth, the Express Scripts chief executive, would serve as president of the Express Scripts business.
Morgan Stanley and the law firms Wachtell, Lipton, Rosen & Katz; and Paul, Weiss, Rifkind, Wharton & Garrison are advising Cigna. Centerview Partners and Lazard Frères & Company, and the law firms Skadden, Arps, Slate, Meagher & Flom and Holland & Knight, are advising Express Scripts.