This is the correct explanation. Their request comes out of trying to limit the damage of this leak:

"Credit Suisse leak unmasks criminals, fraudsters and corrupt politicians"

https://www.theguardian.com/news/2022/feb/20/credit-suisse-s...

Even the Vatican is on it:

"...One Vatican-owned account in the data was used to spend €350m (£290m) in an allegedly fraudulent investment in London property that is at the centre of an ongoing criminal trial of several defendants, including a cardinal..."