UnitedHealth Group on Friday said it has agreed to acquire a health care provider and insurer operating in Chile, Colombia and Peru in a deal that values the South American company at about $2.8 billion.

The deal would expand UnitedHealth Group's operations in South America, where the largest health insurer in the United States already is a large health care provider and insurer in Brazil.

The announcement Friday comes at the end of a year in which the Minnetonka-based company rolled out three other deals worth $1 billion or more, acquisitions that expand United Health's role in the surgery center, medical clinic and health care consulting businesses.

"We continue to move in smart and prudent ways, first in South America and in Europe," chief executive David Wichmann said during an investor conference last month. "We expect to have taken similar positions of significance in other global markets by 2025."

UnitedHealth officials have described the global business as a key source of diversification beyond the UnitedHealthcare insurance business and Optum, which sells a variety of health services.

In a regulatory filing Friday, UnitedHealth said it intends to launch next week a tender offer for Empresas Banmédica as an initial step toward acquiring the company.

UnitedHealth will offer to buy all the company's outstanding shares.

Two controlling shareholders will tender their combined approximate 57 percent ownership, according to the filing, and the deal is expected to close in the first quarter of 2018.

Banmédica provides insurance coverage to 2.1 million people, a UnitedHealth Group spokeswoman said, while operating 13 hospitals and 143 medical centers.

UnitedHealth estimates it will generate about $7.8 billion in revenue from its global operations this year, a small portion of the roughly $200 billion in projected annual revenue.

More than half of the world's health care spending happens outside the United States, the company says, where UnitedHealth Group serves less than 1 percent of the market. UnitedHealth officials say that expanding its worldwide business, through acquisitions and by growing current operations, is a priority.

"We see health systems around the world wrestling with many of the same issues we face here in the United States," Wichmann said in November. "Our capabilities are quite relevant to creating real opportunities for growth. We're seeing that in Brazil, in Portugal and in the U.K."

Earlier this month, UnitedHealth announced a $4.9 billion deal to acquire the medical group business of DaVita Inc. In January, the company said it would spend $2.8 billion to acquire one of the nation's largest operators of surgery centers.

And in August, the Optum division said it would pay $1.3 billion for the health care business of the Advisory Board Co., a Washington, D.C.-based research and technology firm.

Acquisitions have been a big part of UnitedHealth's global expansion, as well.

In 2012, UnitedHealth acquired Amil Participacoes, the largest private health insurer and hospital operator in Brazil, for $4.9 billion. That year, the Amil business announced it was entering the hospital business in Portugal by acquiring a company that operates seven hospitals in the country.

The Brazil operation includes 34 hospitals and more than 100 outpatient and ambulatory care centers.

In terms of population, Brazil is the second-largest private health insurance market in the world behind the U.S. — private health insurance membership overall has grown to 47 million, UnitedHealth Group says, but represents just under one quarter of Brazil's population.

In Brazil, about 4 million people have UnitedHealth Group health insurance benefits and another 2 million have dental coverage, but UnitedHealth says growth has been hampered by ongoing by political uncertainty and an economic slowdown in the country.

"In 2018, we expect health benefits to remain flat to slightly down due in large part to the challenging economic backdrop in Brazil, and we remain steadfast in our pricing discipline," Dan Schumacher, the president and chief operating officer at UnitedHealthcare, said during the November investor conference.

The global business at UnitedHealthcare also includes providing benefits to companies operating in more than 130 countries. Clients include multinational and local businesses, as well as governments and individuals, the company says.

Christopher Snowbeck • 612-673-4744 Twitter: @chrissnowbeck