UnitedHealth Group Incorporated is an American multinational managed healthcare and insurance company

In 1974, Richard Taylor Burke founded Charter Med Incorporated, a Minnetonka, Minnesota-based privately held company. In 1977, the United HealthCare Corporation was created to reorganize the company and became the parent company of Charter Med. United HealthCare's charter was to manage the newly created Physicians Health Plan of Minnesota, an early health management organization.

In 1988, United HealthCare started its first pharmacy benefit management, through its Diversified Pharmaceutical Services subsidiary. It managed pharmacy benefits delivered both through retail pharmacies and mail. The subsidiary was sold to SmithKline Beecham in 1994 for $2.3 billion.

In 1994, United HealthCare acquired Ramsey-HMO, a Florida insurer. In 1995, the company acquired The MetraHealth Companies Inc. for $1.65 billion. MetraHealth was a privately held company formed by combining the group health care operations of The Travelers Companies and MetLife. In 1996, United HealthCare acquired HealthWise of America, which operated HMOs in Arkansas, Maryland, Kentucky and Tennessee.

In 1998, the company was reorganized as the holding of independent companies UnitedHealthcare, Ovations, Uniprise, Specialized Care Services and Ingenix, and rebranded as "UnitedHealth Group". Also in 1998, United Health Group acquired HealthPartners of Arizona, operator of Arizona's largest AHCCCS provider.

In 2001, EverCare, a UnitedHealth Group subsidiary merged with LifeMark Health Plans In 2002, UnitedHealth Group acquired GeoAccess and Medicaid insurance company AmeriChoice. In 2003, UnitedHealth Group acquired Mid Atlantic Medical Services, an insurer serving Maryland, Washington D.C., Virginia, Delaware and West Virginia. Also in 2003, UnitedHealth Group acquired Golden Rule Financial, a provider of health savings accounts.

On July 21, 2003, Exante Bank started operating in Salt Lake City, Utah, as a Utah state-chartered industrial loan corporation. It changed its name to OptumHealth Bank in 2008 and to Optum Bank in 2012.

In April 2004, UnitedHealth Group acquired Touchpoint Health Plan, a Wisconsin health plan. In July 2004, the company acquired Oxford Health Plans.

In December 2005, the company acquired PacifiCare Health Systems. It agreed to divest parts of PacifiCare's commercial health insurance business in Tucson, Arizona and Boulder, Colorado to satisfy antitrust regulator concerns, and also agreed to end its network access agreement with Blue Shield of California. The Tucson business was sold to Cigna. The company acquired Prescription Solutions, another pharmacy benefit manager, as part of its acquisition of PacifiCare Health Systems. This business was later rebranded OptumRx.

In February 2006, the company acquired John Deere Health Care.

In February 2008, the company acquired Sierra Health Services for $2.6 billion. As part of the transaction, to obtain regulatory approval, 25,000 customers were sold to Humana. In July 2009, UnitedHealth Group agreed to acquire Health Net's Northeast licensed subsidiaries for up to $570 million in payments spread out over two years. Through 2010 and into 2011, senior executives of the company met monthly with executives of other health insurers to limit the effect of the health care reform law.

In July 2010, Ingenix acquired Picis Clinical Solutions, Inc., a health information provider for the high-acuity areas of hospitals.

In 2011, Logistics Health, Inc. of La Crosse, Wisconsin, was acquired by OptumHealth. In September 2014, the office buildings where LHI is based were sold to UnitedHealth Group for $45 million.

In February 2012, the company acquired XLHealth, a sponsor of Medicare Advantage health plans with a primary focus on medicare recipients with special needs such as those with chronic illness and those eligible for Medicaid ("dual eligibles"). In October 2012, UnitedHealth Group and Amil Participações, one of the biggest Brazilian health insurance companies, completed the first phase of their merger.

In February 2014, Optum secured a majority stake in the Washington, D.C.-based startup Audax Health. Audax's CEO, Grant Verstandig, continued running the firm alongside COO David Ko. In October 2014, Optum Health acquired the health services unit of Alere for $600 million cash.

In March 2015, it was announced that CatamaranRx will be acquired by OptumRx.

In April 2016, the company announced it was pulling out of all but a "handful" of state healthcare exchanges provided under Affordable Care Act and will continue to sell only in three states in 2017.

In 2017, UnitedHealth's Optum unit acquired Rally Health, a company started by Audax Health's executives Prior to acquisition, in 2015, UnitedHealth supported Rally Health as a majority investor and through enrolling 5 million UnitedHealth policy holders in Rally Health's flagship product, RallySM. The close relations between UnitedHealth, Audax Health and Rally Health follows a close personal relationship between Grant Vrestandig (Audax and Rally) and UnitedHealth's President and CFO at the time, David Wichmann.

In June 2019, UnitedHealth's Optum division acquired Davita Medical Group from DaVita Inc. for $4.3 billion. That year, the company also agreed to acquire Equian for $3.2 billion. On June 19, 2019, UnitedHealth acquired the online patient community platform PatientsLikeMe for an undisclosed amount and it will be incorporated into UnitedHealth Group's research division.

In November 2019, Andrew Witty was named president of UnitedHealth, in addition to his role as chief executive of the company's Optum division.

UnitedHealth announced in March 2022 that it would acquire LHC Group for $5.4 billion. The deal will expand its home health capabilities by combining LHC's services with UnitedHealth's Optum unit.