A verb, not an industry
Most vertical extensions name a sector. .rent names a transaction, and that is what makes it useful and what limits it. A visitor reading brunnenhof.rent knows before the page loads that the building is available to let rather than for sale, which is exactly the ambiguity property marketing usually has to spend a headline resolving. The same holds for hire businesses, where the extension separates the rental arm from a dealership that also sells.
The limitation is the mirror image. Anything you might one day sell, or any business whose model shifts between selling and letting, ends up with an address that contradicts the offer. It is also a weak fit for the corporate layer of a property group, where a holding company, an investment vehicle or a fund needs to look institutional rather than transactional. The workable pattern is a .com or ccTLD for the company and .rent for the individual buildings, developments or hire lines beneath it.
The registry, and the premium list you should read first
IANA records the sponsoring organisation as XYZ.COM LLC, delegated in 2015, with technical operation contracted to CentralNic in London and RDAP served from CentralNic's infrastructure. It is a different registry from the Identity Digital extensions we sell, and its Domain Name Policies are its own document, currently version 2.0. Those policies set the one-to-ten-year term, reserve an unpublished set of names, and reserve the right to allocate reserved names later by auction or premium sale, so absence from a search result is not always the same as somebody else holding the name.
The detail worth an actual look before you commit is the premium tier list, which the registry publishes as a downloadable file. It runs to thousands of labels and covers precisely the words a rental business would reach for first: single letters and digits, home, homes, house, apartment, apartments, cars, and a long run of city names. Critically the tier applies to renewal and transfer as well as registration, so a premium .rent is a recurring cost decision rather than a one-off. We show registration, renewal, transfer and restore pricing on this page for the specific name you search, which is the only reliable way to see which tier, if any, you are in.