[6][7] The deal closed on December 20, 2018 at $54 billion, allowing Cigna to start offering new Express Scripts products to its corporate health insurance customers in 2019.

[8] Express Scripts began in 1986 in St. Louis County, Missouri as a result of a joint venture between a retail chain of more than 79 pharmacies (Medicare Glaser Inc.) and Sanus Corp. Health Systems.

General American Life Insurance Company invested in Sanus's future, the largest part of the funding based in New York.

[12] Sanus rapidly grew and by 1986 it had 200,000 clients and $100 million in revenue, operating in the St. Louis, Dallas, Fort Worth, Houston, and Washington, D.C. markets.

[13] The initial report of the creation said that Charles H. Ridings, formerly in charge of McDonnell Douglas mergers and acquisitions, was named the first chief executive, although he was quickly replaced by Waltman.

With increased investment by New York Life, Sansus change its name to NYL Cares and in 1998 was sold to Aetna for $1.05 billion.

[15] Glaser Drug Company sold its Express Scripts partnership interest back to Sanus before it was acquired by chain SupeRx in 1989 for $18.2 million.

General America had run into financial problems and had said it could not pay back $6.8 billion in short term bonds to investors.

[19] In 1993, Express Scripts signed on both FHP International and Maxicare Health Care and corporate clients Lockheed, Service Merchandise, and Ingersoll-Rand.

[22] In October 2007, Express Scripts acquired ConnectYourCare, and now handles FSA, HRA and HSA accounts for companies such as Suntrust, Zions Bancorporation and Allegis.

[23][24] On April 13, 2009, it was announced that Indianapolis-based WellPoint (now Anthem) had agreed to sell its NextRx subsidiaries for $4.675 billion to Express Scripts.

[27] The acquisition positioned Express Scripts Holding Co. as the largest pharmacy benefit manager, filling 1.4 billion annual prescriptions.

[27] In 2017, Express Scripts launched Inside Rx, a partially owned subsidiary that provides discounts on medications for the uninsured and underinsured.

[28] In July 2017, Express Scripts purchased myMatrixx, a workers' compensation pharmacy benefits company based in Tampa, for $250 million.

[29] In October 2017, Express Scripts lost its biggest client, Anthem, which said it would not renew the PBM contract in 2019 and would instead use CVS Health.

[32][33][34] In November 2017, Express Scripts announced it was divesting United BioSource Corp. (UBC), its pharmaceutical support business.

Insurance companies have charged that the PBM model has contributed to high drug prices because PBMs take a commission on each transaction.

[44] In late 2020, Express Scripts and several subsidiaries were rebranded and reorganized into a distinct health services organization, Evernorth.

[50] Since the move the company has been an active partner with the university including contributing money to renovate the computer sciences building (Express Scripts Hall),[51] raising funds for building projects, sponsoring a pre-collegiate bridge program for high school students and sponsoring a small business incubator.

[52] The southeast portion of the campus is in Bellerive, Missouri[53] and the southwest corner of the two-building complex is in unincorporated St. Louis County.

[62][63][64] Because of its position between pharmacies and health care plans, Express Scripts sees 1.4 billion prescriptions a year, and it uses this information as part of its research data to create better options for clients and patients.

In 2008 the company settled the lawsuit, agreeing to pay $9.3 million to Pennsylvania and 28 other states to resolve claims of deceptive business practices.

A consumer class action lawsuit against Express Scripts was brought on by John Amburgy, a Missouri man, who accused the company of negligence in protecting customer records.