SAO PAULO, Jan 8 (Reuters) - Insurer and hospital operator Hapvida on Friday offered to buy rival Notre Dame Intermedica for 49 billion reais ($9.04 billion) in an all-share deal that would create the country's largest hospital chain.

The companies combined would have 8.4 million health insurance clients, spanning from the country's north and northeast, where Hapvida is concentrated, and the wealthier south and southeast where Intermedica operates, according to a document reviewed by Reuters.

The joint entity will likely be able to cut costs, given that it serves some of the same corporate clients in different parts of the company but the lack of geographical overlap should reduce competition concerns.

Still, the combined companies would have 70 hospitals after the deal, more than Carlyle-backed Rede D'Or, the country's biggest hospital chain, with 51 units.

Shareholders in Hapvida would hold 53.1% of the combined company after the proposed deal, according to the proposal. The deal values Intermedica's shares at 79.86 reais, roughly a 11% premium over Thursday closing price, in a deal of nearly 49 billion reais.

Shares in Intermedica surged nearly 27% on Friday, valuing the company at more than 55 billion reais, while Hapvida was up 18% percent.

Intermedica said it has received the proposal and will analyze the terms, "despite believing in the market potential of the company to remain autonomous and leader in the Brazilian healthcare sector".

Hapvida is controlled by the family of its chief executive, Jorge Pinheiro. Intermedica has private equity firm Bain Capital as a minority shareholder, with a roughly 11% stake.

Banco BTG Pactual and Itau Unibanco Holding are advising Hapvida in the deal, while Intermedica has not hired advisors yet. ($1 = 5.4178 reais) (Reporting by Carolina Mandl Additional reporting by Gram Slattery Editing by Brad Haynes, David Goodman, Cynthia Osterman and David Gregorio)