The interest is the reward for not buying new fancy shoes today. They teach that in high school. But why should I save money when I can only afford sandals the day after tomorrow because of the negative interest rate? Because, unfortunately, the pension funds are also suffering from the negative interest rates, in addition to demographics and the reform backlog, you should take care of your pension provision despite the negative incentive to save, by setting up an extra-mandatory 1e pension plan or a third pillar.
No return without risk
The fact is: negative interest rates preclude a risk-free return. Even the pure maintenance of value costs money. Even 3a account solutions only generate an average of 0.275% interest. You won't get far with that. You can achieve a significantly higher long-term return by investing more in equities. But that in turn involves risks. The first thing you need to do is determine how much risk - i.e. fluctuations in value - you can or want to take. This is your personal risk budget. You should never exceed this, but always make full use of it.
No risk without return
Now it seems obvious to dispense with high-quality bonds altogether, as these only cost like cash. That would be wrong. First-class (government) bonds have a stabilising effect on the portfolio. If the stock markets fall, they gain in value. It's a bit like football: the defenders (bonds) protect at the back so that the forwards (stocks) can score goals at the front. The more efficiently the team or portfolio is set up, the better the result.
An efficient team consisting of bonds and equities
The selection and weighting of individual stocks is therefore important: the risk characteristics - in technical jargon volatilities and correlations - of the individual stocks play a particularly important role. A risk-optimised portfolio allows a higher proportion of equities, and thus a higher return for the same risk budget. The focus on risk therefore pays off in the long term, especially when an end to the low interest rate policy is not in sight.
