The bank said that contact data (but not passwords) of 481 subscribers to the site's newsletter may have been captured, including email addresses, names, positions and titles. It said that no market-sensitive data had been compromised.

The ECB launched the site in 2015 to help bankers produce statistical and supervisory reports.

A few weeks ago it was reported that , the fifth-largest US credit-card issuer, was hit by a hacker who accessed personal information of about 100 million card customers and applicants. That case was shocking, even by the standards of big attacks on Equifax and JP Morgan, to give just two cases. (In the JP Morgan incident, 76 million accounts were affected.) In the Capital One case, about one million Social Security numbers have been compromised. Cyber-security remains a major issue for wealth managers, given the obvious allure of its money.