Looking at wiki’s list (Shipping line - Wikipedia), Finland, Norway and Greece seem to have a lot more than you’d expect. Do they have laws or regulations that make it easier or cheaper to run ships from there?
For Norway at least: a long coast leading to a tradition for shipping, low cost labor (until we found oil, now there are no Norwegian crews on anything), aaand. Well that’s it basically.
It’s not cheaper or easier, cause the shipping companies constantly threaten to move out because they’re not getting enough preferential treatment.