Africa's only female billionaire is sending Portuguese bank shares through the roof

Isabel dos Santos, the daughter of the president of Angola and Africa's youngest and only female billionaire, is sending the share prices of two of Portugal's biggest banks surging.

A source told Reuters that dos Santos wrote to the CEO Spain's Caixabank, suggesting a merger of two Portuguese banks, Millennium BCP and Banco BPI.

Caixabank already owns nearly half of Banco BPI, and dos Santos owns nearly a fifth. A merger between the two was suggested back in 2007, but never saw the light of day.

Both banks are both enjoying the news. As of 3:15 p.m. GMT (10:15 a.m. ET) Banco BPI shares are up by 8.24% to their highest level since December, and Millennium BCP is up 3.7% to levels last seen in November.

The Financial Times notes that the new entity could not only be Portugal's biggest lender, but also be majority Angolan-owned.

Here's Peter Wise at FastFT:

Sonangol, Angola's state oil company, is by far the biggest shareholder in BCP with 20 per cent. If a BCP-BPI merger were to go ahead, Angolan investors would probably be the biggest shareholders in the new entity.

However, a potential merger between BCP and BPI would have to clear massive regulatory hurdles, given that both BCP and BPI received state aid during Portugal's recent bailout and that BPI is seen as a leading contender to buy Novo Banco, the "good bank" created out of the ruins of Banco Espírito Santo, which collapsed last year.

Portugal's banks often have major business interests in Angola, which was a Portuguese colony until 1975. So Angolans are pretty used to Portuguese business interests affecting their own country. But it's not quite as often that an Angolan billionaire reaches back in the other direction.