How long can the owners keep your deposit? My owner is saying that he can keep it for like 6 months!!!!

Up to 12 months was my understanding.

http://www.asi-infoalloggio.ch/

From previous posts on the forum, I believe what your landlord says is true. However whether he chooses to exercise his right or not is a different matter, I haven't had this problem in the past with the deposit paid within a week after the handover process. Any additional "Neben Kosten" would be billed seperately but this is unlikely.

Usually it's the small landlords that play these dirty games...

Actually, some of the larger property managers can be extremely difficult with regards to releasing the deposit.

I have been told that the settlement process (after final inspection) typically takes 3 months and it seems that the deposit can be returned anytime within a year. There should be a clause in your agreement which states this (in German of course). The argument is that your money is earning interest and hence you should not be worried And, I wonder how much my money is earning

It can be held up to a year and after that you get it back if no claims have been made. It takes 13 months in total but that is only if the property company is a real ass.

Do the owners actually have your deposit? Or is it in a bank account in your name requiring their signature to release the funds?

Search the forum, it will tell you all but yes it should be in a special account as you said.

In my case he keep the deposit from the previous rent, ( who is my friend) after a month I was living in the flat. Why? because we as a new rent we have ONE month to say something is wrong, after that we have to pay