According to German law a medium sized companies for fills at least two out of the three criteria of having a turn over of 50million+, 25million+ in equity or more then 250 employees on average over a year. It is a common trick, to fool people into thinking that they are middle class or your local restaurant, craftsmen, architects, small stores and so forth.

Any decent wealth tax 100% should hit medium-sized businesses. Owning such a company puts your net worth in the 10s of millions.