All the above is pretty understandable; and I basically agree without hesitation. The background of my little uncertainity was a specific situation that follows:
Yes, Erste Bank in Montenegro︀ cannot access client data of Erste Bank in Austria, similarly e.g. with Deutsche Bank Polska︁ and Deutsche Bank Germany. They are independent legal entities, having separate infrastructure, etc.; they only︂ have the same owner/belong to the same group. But, for example, at Polish market there︃ also operates (or at least operated) Bank of China (Luxembourg): it has a branch there︄ (it has small market share, serving some chinese companies and some individuals, but it is︅ not important now). It is just a branch, appropriately registered. Frankly, I doubt that this︆ small branch has sufficient infrastructure to be able to perform all the functions independently of︇ the company headquarters; I guess that some data really have to be shared (and I︈ do not see it as being criminal). (BTW, this branch even – AFAIK – do︉ not participate at Polish Bank Guarantee Fund, the deposits of clients are covered by Fonds︊ de garantie des dépôts Luxembourg.) And the situation of ProCredit DIRECT Macedonia seemed to me︋ a little bit similar, my impression of their webpage (I had known before about ProCredit︌ in Germany but for Macedonia I was checking the web) was that the ProCredit was︍ the group with very tight connections, seeing local entities more of less like branches... So,︎ if the data sharing is (probably) possible in one case, why not in another?
But really, it is possible that I am completely wrong; I was never in such a️ situation that I was afraid about similar data leakage, so I have no experience. (On the contrary, a few times I encountered the situation that the local entity of a big bank in country A helped me – or someone known to me – to manage something with the local entity of this bank in country B, so I was happy with some de facto data sharing 😉 )
Yes, unfortunately.
Another question is, to what extent this protection is bullet-proof (or perhaps corruption-proof, especially︀ in some countries); but it is a different problem – and as you said, “If︁ that's your risk scenario, then no financial service provider is safe.” 🙁