Banco Santander Totta S.A. is a Portuguese bank.
Banco Espírito Santo is a private Portuguese bank, based in Lisbon.
Portuguese banks hold strategic stakes in other sectors of the economy, including the insurance sector.
The couriers bypassed the Portuguese central bank and sold the gold locally.
That step, if taken, would provide more banking options for major international corporations, which are now served almost exclusively by Portuguese banks.
Electron debit cards issued by Portuguese banks cannot be used for postal transactions.
These cards use the "chip and pin" system and Portuguese banks do not offer the facility for remote transactions, including postal and telephone payments.
This stance pushed shares higher across Europe and helped the euro to strengthen, as fears abated that Portuguese banks would soon struggle to finance themselves.
If the ECB stuck with its normal rules of refusing to accept junk bonds as collateral, it would have cut the lifeline to crisis-hit Portuguese banks.
Portuguese banks are looking distinctly wobbly now, having absorbed toxic bond issues with ECB money their behaviour is now dubious.