99.99% for-rent apartments I’ve seen in Western Europe were owned by some huge company. That’s a stark contrast to Eastern Europe where you’re much more likely to rent a privately owned property.
This may be because of local laws or city council rules. In many cities the developer of a complex today is forced by law to have a certain percentage of the development dedicated for rental (Munich I think may be the leader here with a proposed 80% for rental). The only way to achieve this is to have the apartments owned by the developer or handed over to another management company (or investor) for rental only.
It's also why you sometimes see a development with a several rows of houses meant for sale flanked by one or more apartment buildings with a far smaller footprint but enough floors to equal roughly the same usable area in order to get the project approved.
actually in Germany 60% of the appartments are owned by private individuals 10% state/local governments, 10% coops (Genossenschaft), and the reminder corporations. (While statistics differ a bit depending on where you draw the line between some private owner and a corporation for auch a statistic)
https://www.savills.de/insight-and-opinion/savills-news/2756... is one survey with some numbers
The laws I mentioned are relatively new [0]. So for now it's hard to compete in numbers with a century of already built apartments. And eventually all "for rent" units do go on the market for sale.
But it's also easy to see why for someone looking for rent in many big cities today it looks like most apartments are owned by big management companies. New developments in "hot" cities with high demand and such laws are owned by a management company because that's the only way it works. You'd see entire buildings owned by the developer. It will take decades for those new apartments to go into private ownership.
It's also why you sometimes see a development with a several rows of houses meant for sale flanked by one or more apartment buildings with a far smaller footprint but enough floors to equal roughly the same usable area in order to get the project approved.