You know, East Coast, Der Spiegel has really deteriorated in quality over the last decades.
To me, the beginning of the article does not sound credible, Germany in the 1990s, a 13 year old minor having a stock trading account, lol. I have worked at a bank back then and I highly doubt it.
Even an own bank account for minors was unusual then, though possible.
So I have my doubts about the accuracy of what is written in the rest of the article.