UnitedHealth Group Inc. said on Friday it signed a definitive agreement to buy Chilean healthcare company Banmedica SA for $2.8 billion, expanding the health insurer's footprint in South America.

Banmedica operates health insurance, clinics and other services.

UnitedHealth will offer 2,150 pesos per share and the two controlling shareholders of Banmedica will tender their combined 57 percent ownership, the U.S. company said in a regulatory filing. http://bit.ly/2Bm24tw

The companies had signed a non-binding agreement in September.

"We view international as a selective supplement to UNH's growth, while the primary growth driver and M&A focus will be building out the vertical integration strategy with Optum (UnitedHealth's unit) in the U.S.," Evercore ISI analysts said in a note.