The banks said they now considered Cuba a "sensitive" country - along with Iran, Myanmar, North Korea, Sudan and Syria.
A spokesman for Credit Suisse told Reuters that the bank had decided not to enter into new business with these "sensitive" countries since the start of the year.
Referring to Cuba, the spokesman added: "We do not do payments in U.S. dollars but payments in other currencies are possible if we can find a correspondent bank. But this is very difficult."
And yes, you can expect the Castro regime and its apologists to blame the US commercial embargo for the decision by the Swiss-based banks to institute their own boycott.
However, AFP quotes a spokesman for UBS, Christoph Meier, as saying the reason for the boycott is because "it costs too much to ensure that Cuba respects and conforms to legal and financial regulations".