What should I be aware of if I want to pass the apartment on to my siblings as a gift or inheritance instead of cash?

Your list contains two very different types of questions — I can only help you with the tenancy law part.

What I can answer (Tenancy Act):

- The tenancy is not at risk, regardless of how you transfer the apartment. Your tenant has lived there for 7 years and is protected by the tenancy law regardless of ownership change — it is you as the owner who changes, not the tenant's rights. According to § 117, subsection 7, the new owner takes over the maintenance obligation and continues the maintenance account upon ownership change, which supports that the tenancy continues unchanged. - The offer obligation is usually not triggered. If you transfer the apartment as a gift or by inheritance, the offer obligation according to § 198 in other cases could mean that the tenants (via a cooperative housing association) must be offered to take over the property. But according to § 198, subsection 2, no. 2 and 4, the offer obligation does not apply when the acquirer is related to you in the sideline "as close as siblings" — that is, precisely your siblings — or when the acquisition takes place by inheritance. Both forms of transfer you are considering are therefore exempt.

What I cannot answer (outside the Tenancy Act):

- Gift tax, estate tax, and taxation upon transfer - Liability for mortgage loans and debt to the owners' association between you and your siblings - Advance inheritance rules and impact on your and your siblings' personal finances

This is tax, estate, and inheritance law, not tenancy law, and I do not have the basis in my context to give you precise rates or rules here. You should clarify this with an accountant or a lawyer specializing in inheritance and gift tax before you decide on a gift, gift letter, or pure transfer by inheritance.