House purchase from uncle - Monthly payment or take a loan?

Maybe this can still be stipulated in the purchase contract by the notary

Yes, that is possible. Emotionally easier for everyone is the separation into purchase and loan.

If the property is entirely in your ownership in the event of the uncle's death, any increase in value will naturally and rightly benefit the other heirs as well, since they inherit ownership proportionally

??? ... that is not logical at all.

I suspect that hampshire forgot the word "not" in "completely in your ownership"

If that is the case, it is important to make a purchase contract and a loan agreement. And even if everything is perfect now, IN WRITING :cool:

We all get along great in the family,

I hear that every day in the past tense – only the current situation no longer is :D ;) Be that as it may:

Option 1: I pay him €20,000 per year over 15 years, so €1,666 per year with 0.5% interest (legally the minimum) Option 2: I take out a loan of €200,000 or even €300,000 and pay him the purchase price of €300,000 directly.

Since option 3, liquid funds not available (since when does a stock portfolio count as assets?), is out

So I definitely want to keep around €150,000 invested in stocks,

option 2 remains! :) Option 1 is neither here nor there...

Since option 3, no liquid funds present, (since when does a stock portfolio count as assets?) is not applicable

That would be a way to turn real assets out of the portfolio, because nobody has a crystal ball