Western Germany: "Not so known" locations produce higher yield

Institutional investors are traditionally looking for investments where the Germans earn their money: Munich, Hamburg, Düsseldorf, Frankfurt, Cologne, Stuttgart.  What about the cities right next to those locations? The German managment magazine "Manager Magazin" published an interesting article yesterday (here in German o-version) in which they have a closer to look to where investors
really have opportunities. 

My office is located in Berlin. Since I moved from Barcelona to Berlin in 2006 I have been telling my clients to not go down the path where they will have to shake hands with their direct competitors. So far I was not lucky in convincing them; therefore I am glad I can once again refer to a publication whose authors must have read my mind over the last years. But they go even further.
They are not saying "forget Berlin" (which is also not a really good advice), they tell you to take the calculator out and use it! You cannot help but ending up in cities like... Wiesbaden. 

Use your calculator and have a look at Hamburg, Munich and Düsseldorf. It is difficult to earn 3% net at the end of the day. The winner of the study is:

• Wiesbaden
• Aachen
• Freiburg
• Frankfurt

The "loosers" of the study are:

• Stuttgart (did not even make it into the ranking anymore)
• Munich
• Hamburg
• Düsseldorf