The report states that the European Central Bank (ECB) has also understated "the household wealth per adult in most Eurozone countries, with the notable exceptions of Cyprus and Malta."

An ECB Household Finance and Consumer Survey suggested that the average wealth in Germany was lower than that in Cyprus and Malta.

Credit Suisse dispute the result because the bank's country comparisons are framed in terms of wealth per household, which vary in size across member states. Credit Suisse says a better comparison is wealth per individual.

They also estimate that the ECB uncovered only 79 percent of non-financial assets in France and exaggerated non-financial assets in Cyprus by a factor of almost five and in Malta by a factor of almost eight.

"Our value is about 20 percent higher for Finland, Germany and Greece, about 35 percent higher for Italy and the Netherlands, and 50 percent above the ECB level for France," says Credit Suisse.