Tenet Healthcare Corp. is buying Vanguard Health Systems for about $1.8 billion, helping to expand its service offerings and broaden its geographic reach.

The companies said Monday that the transaction also includes $2.5 billion in debt and value the entire deal at $4.3 billion.

Tenet will pay $21 per share, a 70% premium to Vanguard Health's Friday closing price of $12.37.

Nashville, Tenn.-based Vanguard Health says its founder, Chairman and CEO Charlie Martin, will join Tenet's board.

Tenet expects annual savings of $100 million to $200 million and for the acquisition to add to earnings in the first year.

Dallas-based Tenet has secured fully committed financing for the transaction from Bank of America Merrill Lynch.

Both boards unanimously approved the deal, which is expected to close before year's end.