LISBON (Reuters) - Angolan investor Isabel dos Santos formally registered her offer for holding company Portugal Telecom SGSP (>> PORTUGAL TELECOM) on Monday, a spokesman said.

The bid made by the daughter of Angola's president is intended to thwart the sale by Brazil's Oi of Portugal Telecom's operations to telecoms group Altice (>> ALTICE) for 7.4 billion euros (5.86 billion pounds)

The bid comes despite that fact that Oi and Altice agreed on Sunday on the sale.

Oi acquired the Portuguese telecoms assets through a merger with Portugal Telecom. Through that merger, the Lisbon-listed holding company Portugal Telecom SGPS' only real asset is a stake of about 26 percent in Oi, which dos Santos hopes would be sufficient to block the sale of PT's assets to others.

Dos Santos' company Terre Peregrin had earlier said it was offering 1.35 euros per PT share, below PT's current price of 1.4 euros a share.

(Reporting By Sergio Goncalves, writing by Axel Bugge)

Stocks treated in this article : PORTUGAL TELECOM, ALTICE