Future planning: special repayments yes or no?

Your condominium will later become your equity.

Perhaps as an addition here, this only applies if the financing bank for the new property is the same as for the existing condominium. If the "new bank" cannot take the condominium as first ranking collateral, it will not include it in the loan-to-value calculation.
Therefore, you should only make special repayments once it is clear that the apartment will be sold again.

Now we are considering whether special repayments make sense or whether we should rather keep the money as "equity" and invest it (e.g. ETFs / real estate funds). Now we are considering whether special repayments make sense or whether we should rather keep the money as "equity" and invest it (e.g. ETFs / real estate funds). We still don’t know whether we want to keep the apartment here and rent it out or sell it. What do you think about that?

Basically, a special repayment is quite poor from an investment perspective. In your case, it is equivalent to a fixed-term deposit with an interest rate of 0.92%. The average market return is somewhere around 6%. Of course, you don’t achieve this through brainless investments in highly volatile gambling securities, but a well-thought-out strategy should yield 10%+ in the future as well.

In my view, investing in real estate funds when you have bought a condominium makes no sense, unless you live in a region that is not anticipating the current ongoing real estate boom. Otherwise, you already have a substantial chunk invested in real estate, so why increase the concentration risk further?

I am not a fan of renting out. In recent years, appreciation has significantly outpaced rental yield. Since you currently still live there yourselves and plan to do so for a while, paying down the loan will completely destroy the leverage effect from borrowed capital; one should be aware of the disastrous effect special repayments have on this. You live there long enough to ignore taxes and prepayment penalties.

If you absolutely want to rent it out, avoid spending a single cent on the apartment.

In the end, it depends on your risk appetite how you distribute your money. My arguments are based on historical experience and do not necessarily have to hold true for the future.

Keep in mind that, for example, price increases of "only" 3% can mean that in 10 years you will need not €600k but €800k or more.

A well-thought-out strategy should continue to yield 10%+.

Tell me about it.

Tell me.

An investment in an MSCI World over the past years would already have generated a higher return than the mentioned 10%. On average about 7% over the past 50 years.

No one can give you a guarantee (especially short-term). But the OP is talking about an almost 10-year horizon. In that case, market performance is a good approximation as long as you don't move your money back and forth every 2 weeks to invest in the next Tesla.

An investment in an MSCI World over the past years would have already generated a higher return than the mentioned 10%. On average about 7% over the last 50 years.

Which tends to suggest that the next years will be below average. At least under the assumption that the average value remains constant. Double-digit return expectations are rather unlikely in the long term. The last years were a special situation, fueled among other things by historically low interest rates and possibly also by the technological shift (MSCI "World" consists of almost 20% American IT companies). But a decent dividend yield is 2-3% and including capital gains 6-7% (before taxes!) is also significantly higher than the 0.92% (tax-free!) from the loan ;) The downside is that you have to sell at a relatively fixed time if you want to use the funds as equity. And you should avoid timing problems

Exactly the other way around when you want to rent out.

Hi, that’s correct, I hadn’t thought about the tax advantage. Only with the currently low interest rates, it’s not that significant here. Regards Olli